B.M.
Well, the definition of a gifted child is unbalanced development. So, if he's ahead academically and behind socially that's pretty "normally abnormal" so to speak lol!
In terms of teaching him to channel his frustrations I find that tae kwon do can work WONDERS. Also, get him into a sport where there are other kids around but NOT a team sport - ie; swim team. So, he's burning energy and around kids, but doesn't have the pressure to fit in and therefore the frustration when things don't go his way.
I also think that (if you don't already) you can start having conversations with him that A. validate his feelings of frustrations and B. give him very clear and very explicit examples of both what is OK to do and what is NOT ok to do.
For example - "I know that you are really really mad right now. Would you like to go run around the backyard (go to your room and count to 150 etc) because hitting is not ok".
The pouting I would either ignore or send him to his room to 'change his attitude' (we used to have a box of attitudes in the closet from which my daughter could 'pick' a new one).
Good luck!