C.D.
If I had the money and there was a Waldorf school in my area that would perfect. If not, the next best thing is a Montessori school.
If his behavior isn't great there is a reason and probably has to do with the teacher and maybe too much emphasis on academics. Often what happens in children who naturally take academics so quickly and easily so early later become burned out and numbed to learning any more of it. Balance is key. He's just started. Think of the meaning of what he is learning and how he's learning it. To get to a child's mind you must go through the heart.