Hello and thank you for consulting JA,
I certainly agree with Howard's suggestions about positive behavior management.
Here's another thought: it is possible that he does not have much control over his behavior. Sounds like he is able to control it at school but then, due to the energy it takes and the fatigue that result, he "let's it all out at home".
What I am suggesting is that he may have Attention Deficit Hyperactivity Disorder. Here are the DSM-IV (a manual used by mental health providers to diagnose) symptoms: http://www.cdc.gov/ncbddd/adhd/diagnosis.html
The aggressive behavior (while not mean spirited) can be due to the impulsive component of ADHD (acting before thinking).
If you think this is a possibility, consult with his primary doctor about the usual treatment. The treatment, medication, is usually concerning to parents. However, the behavior management techniques will not work if it is ADHD because it is a biological condition of the brain which makes sustaining control impossible. If untreated, it can start to interfere with grades even in the brightest student. This usually happens as the educational material becomes more abstract (4th grade).
Just my thoughts.....hope this is somewhat helpful....Warm regards,