My son is 11 and has been in Boxing for about 1 1/2 years now and loves it. It gives him focus, drive, respect of another person (knows its not just about beating a person up or smashing their face in) and discipline. We're talking regular boxing here too (Mike Tyson, Muhammad Ali, Rocky, etc).
They train them in weight lifting, stamina and techniques of stance, amoung other things. My son hasn't been in a real match yet (because he feels he isn't ready for it yet), but he does spar. His coaches are like his 2nd family, they are concerned, at all times, about his health (mentally & physically), his grades, his attitude and how he is involved with his community...its all part and partial of boxing.
If this is something your son wants to do, let him try it out...you never know whether it will actually like it or if you might grow to like it...you might end up disliking it even more, but at least it is something to look into. Just know, once you make the committment, its along term thing...that does have great benefits all long the way...
I've even thought about taking it up (and I'm 34), not only to get back into shape, but to better myself and reconnect with me...it does take alot of drive and focus to get into the ring and out wit someone and beat them and not just with punching!!
Good Luck and hope this helped! God Bless!