How are his verbal skills ? Often anger is a result of frustration. Is he not able to get his point across ? Is it a mechanical issue - like he can't physically DO what he wants to be able to do ? Or is it that he wants to make a decision, and he's being thwarted by the rules of the house ?
Try to figure out the source of his frustration. Out of 4 children, I had one who would really get angry -- the oldest -- and our youngest is more "out there" when she gets angry. those two are extroverts, and the other two kids are introverts, so they internalize the feelings and don't share them.
What we have always held to is that it's okay to be angry. It's an emotion, and it happens. It is NOT, however, okay to express that anger in a way that will hurt another person or destroy things. So when the anger is causing outbursts and poor behavior, the kids had to go to their rooms. both have been threatened with having the hinges removed and their doors removed, due to slamming, but thankfully the doors are still in place. When they calmed down and wanted to be part of the family again, they could decide to return to the family rooms. What that did was give them the gift of time -- and a little solitude -- to pull themselves together and it said that you can be angry, but anger isn't something we take out on other people. So they get to decide whether to control their anger or not, and they get to decide when they are ready to be with people again.
Frankly, my eldest learned this very well for when she was in public, but when she was home, she was still angry alot. As an adult, she now has an excellent and demanding job that she loves, and she handles herself beautifully in public. When she is stressed, she exhibits more frustration with family than with anyone else, but that's the way it ought to be. she lets her hair down with us, because it is safer to be more honest about her feelings with us.