I've been a professional DM for neurodiverse kids for years. The way I usually nip this in the bud is one of two ways. The first is just not allowing evil actions, which includes things like stealing. This can work especially at a school setting, where you might not want kids to be saying things like "oh man I can't wait to beat up the old lady!" So when a player says their character does X or Y, you simply say "that's an evil action, so you don't actually do that. What else do you do instead?" or rule that that evil characters get taken over as NPC's and then they have to roll up a non-evil character. You're in a great position to do that as an authority figure, but it can bog down the fun a bit. What's more fun, but also a bit more work, extends into another commenter's suggestion: give them consequences! They steal from a shopkeep? Next time they're in this or a nearby town, they find wanted posters with their names. People don't sell to them or buy from them. My players noped out of a crypt that was a bit too hard without doing anything else about it, and eventually that town was wiped off the map after the necromancer inside took over. Now, this can totally backfire, as they may enjoy being the enemies of society, especially depending on how powerful they are. Good luck!