Turk - if you drop him back a year level he is guaranteed to score constant A's. You have to try with all your might to change your mindset now he has skipped a year (but even if he didn't its hard to get excited when you see C's everywhere, its a SILLY system with the ABC, when C means GOOD...)

Now he has skipped a year, thats the academic side covered. So please, please make sure you cover his socialization. Its not going to be easy for him to cope between 2 peer level groups. Does he play with the kids his age at lunchtime, even though he is not in their classes? Does he have anything in common with his older classmates, does he play with them too?
Encourage friendships and have his buddies over after school from time to time, I can't stress the importance of after school friends.

xoxoo