Welcome and Welcome back JJ'smom!
Heal Well, and start planning your escape routes. Of course I hope he'll get a wonderful teacher who really gets him and you wont need to do anything of the sort, but I would start 'Formal Afterschooling' now so that DS gets used to working at his readiness level with you, every school night, even if only for 10 minutes, as a formal family tradition.
I have seen kids do well, even with far out abilities, even without grade skips IF they have the kind of relationship with their parents when the parent demands and expects the kid to work at their readiness level even though the other kids in class aren't expected to do anywhere near as complicate homework. I know one mom who arrived in school one the first day with her daughter and a stack of workbooks that she 'expected' the teacher to give the child to do instead of the regular seatwork. And the teachers always did. (The family was unusually high status in their very small town, so mere mortals like us may have a harder time.) Still, the girl sat at her desk right next to the teachers desk all through elementary school and personally that is like a nightmare to my mind. Talk about your 'least worst option.' She has grown into a lovely young woman.
To be honest, it takes a certian amount of flexibility in a kid's personality for this to work well. My kid was not having any of it, and understood that he could make everyone around him just as miserable as he was. If idle hands are the Devil's tools, then my son's idle mind was like a whole machine shop! So document document doument what his abilities and behavior is like now, before school, so that when someone tells you he has a behavior problem, you can bring in dated work, in his own handwriting, that shows that no - he and the school have a 'educational readiness level' problem. I pray it doesn't happen to you, but better to be prepared.
Love and More Love,
Grimity