This here is just my explanation of why I sort Scorp into Gryffindor. The idea is an old one, but this version is mine. Per usual, most of it belongs to the unbelievable JKR. Enjoy!
"Malfoy, Scorpius!"
Whispers buzzed around the Great Hall as a tall, blond boy approached a wooden stool in front of the room. Every eye fixated on him, but if the boy knew, he didn't let on. His dauntless gaze aimed forward with hishead held high as he climbed the stairs. A bald man with cold eyes—the Deputy Headmaster—picked up a shabby hat off the stool in front of him and shot the boy an unfeeling look, sending a shiver down his spine that gave Scorpius the distinct impression the man could read his mind. Unwavering, the young boy looked him straight in the eye before turning around and facing the student body. Scorpius raised himself to his full height—some 57 inches—and gave the school a defiant glare before the hat fell over his eyes. Scorpius waited silently with his hands on his knees.
Suddenly a voice spoke in the darkness. 'It's alright to be scared.
Scorpius scowled at the accusation. "I'm not scared!" he retorted. I'm not scared of anything.
If it was possible for a hat to chuckle, that one did just then. 'No,' it whispered in his ear. 'I don't believe you are…' The hat trailed off as if lost in thought. Scorpius imagined a small, invisible man tramping into his ear and rummaging around his brain. The thought was a little discomforting.
'Let me see…let me see…' it said. 'You're quite the little puzzle, Mr. Malfoy.'
Scorpius couldn't imagine what was taking so long. Everyone in his family had been in Slytherin at school and no one ever considered any other options for a Malfoy. It wasn't "if you get into Slytherin, Scorpius" it was always "Scorpius, when you get into Slytherin…" The eleven-year-old didn't see why the hat even needed to think. His dad said he'd been pronounced Slytherin as soon as he sat down.
'Do you want to be like your father? the hat asked curiously, interrupting the boy's thoughts.
Scorpius considered this for a moment before deciding, No, I don't. He's scared of everything. I don't want to be scared. And I don't like apologizing.
Images of Mr. Malfoy expressing remorse and regret again and again over something no one bothered to explain to Scorpius flashed through his head. He remembered the look on his father's face when he explained to Scorpius why they couldn't visit his grandfather. "He did something bad," his dad told him. "We both did, before you were born. Something very, very bad." No one told him what it was. No one told him why Scorpius and Mammy couldn't see grandfather or why his dad had to feel sorry all the time.
Everyone though Scorpius was too young to know the truth but he wasn't stupid, he understood what they didn't tell him from what he saw and heard, and it all made sense with what they chose to tell him. He knew his parents were friends with Voldemort and hurt people. He knew that there were a lot of witches and wizards who didn't like his family because of that, but they didn't talk to Scorpius so he ignored them.
On the train some smart kid had tried calling his grandfather a psychopath and his dad a spineless killer. Scorpius wasted no time in bloodying the boy's nose. Afterwards everyone left him alone. He sat with Charis Scabior and Laura Flint on the way to Hogwarts, but neither of them talked to him more than was necessary. That was fine with Scorpius anyway, they were both idiots and thought they were cool because they swore a lot and called other kids "mudbloods" and "blood traitors" and stuff. They wouldn't have been so stupid with a grown-up around.
Scorpius watched the landscape fly by as he remembered the last thing Mum said before he boarded the train. "Watch what you say, Scorpius. Be smart, be careful, and always, always be aware of yourself and your surroundings. Did you hear me, baby? Promise me now, promise mummy." Scorpius promised.
I promise, mum, he thought.
'Now that's very interesting,' the hat replied lowly. Scorpius almost forgot about the hat with his eyes closed, and at the hat's reminder as to where he was, sat up straight.
'Very interesting…'
What is? Scorpius wondered.
'Yes, yes…'
What's interesting? The boy questioned, annoyed with the rubbish piece of fabric.
'I've decided—oh, this is very good, very good!—you, young master Malfoy, shall be…'
"GRYFFINDOR!"
The hall quieted, just as stunned as Scorpius. All his life he'd imagined that he would be in Slytherin like the rest of his family. No one was in Gryffindor. And, he thought as the hat was pulled off his head and the hesitant applause turned into confused, but hardy cheers, everyone else had the same idea.
Scorpius finally faltered as he walked in a daze down from his perch and headed for the Gryffindor table. He saw the bewilderment on everyone's faces and hoped to Merlin it didn't show on his. The boy walked tall and did his best to look like he belonged. Nervously, he searched the long table for a place to sit, trying not to notice the number of eyes avoiding him. Scorpius settled on a boy that had been sorted towards the beginning of the ceremony who smirked and scooted down the bench. Scorpius nodded gratefully and walked over, taking his seat silently.
"Evan Griffiths," the boy introduced himself, offering a hand. Scorpius took it and opened his mouth. Evan waved his hand and interrupted, "No need. Everyone's going to know your name now." He grinned at Scorpius' skeptical look. "Don't tell me—" he laughed. "You ain't even a bit surprised?"
It took a moment for Scorpius to understand the boy was referring to the Sorting and agreed somberly that everyone was probably talking about him now. Not exactly his ideal first impression. The eleven-year-old silently grasped onto the belief that by the end of the night, there would be far more exciting things to occupy them all. Scorpius thought he ought to say something, before he could think of anything, however, Evan clapped his back and spoke again.
"Way to go, mate! Really. You showed 'em they can't write you off. I mean, Gryffindor! Tha's just pure genius, that is. Hufflepuff just wouldna had the same effect."
Scorpius hadn't really thought about it in that way; and he didn't exactly dislike the notion. He didn't like people assuming he was one way or another just because of who his parents are. And it wasn't just people disliking him, either. That he could almost handle. What really got on his nerves were the bunch of dolts who just thought they'd very much like to be his friend 'cause his father was a Slytherin and that meant they were sodding soul mates.
Evidently Evan had been mulling the same thing, because his smile broadened and announced another idea that came into his head, "Yer the Boy Who 'Em Proved Wrong, get it?"
Yeah, Scorpius got it. Evan mistook his blank face for confusion and attempted to explain his joke.
"Like Harry Potter? because ya know yer parents are Death Eaters or whatever…"
His dad and grandfather, actually, but Scorpius didn't bother to correct him. In fact, the blond boy doubted whether or not Evan would hear him even if he did speak up. He appeared to be having a good old jolly time by himself, laughing at his own joke. Brilliant, Scorpius thought, rolling his eyes.
"Oi! Griffiths, shut the hell up! You can talk to your boyfriend after the Sorting's over," someone hissed a little ways up the table.
Scorpius turned to see an older boy with wavy brown hair and glasses. He seemed like a pretty cocky guy. Scorpius observed the large "P" pinned to the front of his robes and guessed it accounted for his smug grin.
"Shove off, Sheppard or I'll tell Lina who I saw you snogging at the train station." Evan turned to Scorpius and quickly explained, "Nancy boy here is a lot more than he looks. First he confounds my sister long enough to get her to go out with him, then he goes and snogs the first girl he sees."
Sheppard looked visibly paler, but didn't falter. "No you won't, squirt."
"Wanna bet on it?" Evan challenged with a little more gusto than needed.
Scorpius' eyes widened, thoroughly impressed. Not so much with Evan's brains, but with how cavalier he was about blackmailing the older boy. He knew for a fact Evan wouldn't be able to perform any spells, even if he knew a couple; and if by sheer luck he did, this Sheppard guy looked like he could hex the boy into oblivion before Evan finished saying his incantation—not to mention give him detention. Evan made an ugly face at Sheppard and turned his back to him and spoke once again to Scorpius, though in a lower voice.
"Ignore him, I'll give it ain't easy since he never shuts his gob—" Pot, meet Kettle. "—but he's all bark. Gotta be the only thing Celina sees in him. Oh look here comes Potter! Hey, four-eyes, what took you so long? I thought the hat was trying to put you in Slytherin." A huge grin spread across Evan's face.
Scorpius tried not to turn too quickly to look at the boy approaching. He'd seen Albus Potter on Platform 9¾ when their parents dropped them off and again after he was pulled off the stupid boy from the train. He hadn't said a word but just looked at him curiously until his pretty cousin pulled him away—the younger one with the bushy red hair—shooting Scorpius a dirty glare. Albus was looking at him the same way, only briefly acknowledging Evan's rambling to roll his eyes and shake his head, silently sharing a he's full of crap joke with Scorpius.
The dark haired boy sat down on his other side and smiled, ruffling the back of his head, causing his already very messy hair to spike out more. "So, Scorp," Albus started. "What do you think your parents are going to say?"
That was a no brainer, his dad would be upset, try to pretend he wasn't, and his mum would berate Scorpius for not making the hat put him in Slytherin. But…Scorp? No one had ever given him a nickname before, well, except for his mum, but there was nothing cool about "baby" or "Scorpey-dorpey". Scorp. Scorp. Scorp… He liked it. And for the first time that day, Scorpius finally felt like he belonged. Really belonged. Not just doing what every other magical eleven-year-old in Great Britain was doing.
"They won't say anything," Scorpius grinned. "They'll just whip out their wands and kill me on the spot."
Albus and Evan looked at him with surprise and hesitant smiles, not sure yet if he was joking or actually serious.
"This feast better be good," Scorp continued, gesturing at the empty plates in front of them. "If I'm going to die, I want it to be on a full stomach." His straight face broke into a grin and the other two joined. The boys all laughed and, under the disapproving eye of Hammond Sheppard, spent the rest of the Sorting Ceremony making whispered jokes about their families.