A point I have made before, on behalf of my own children, and also on behalf of my students, is that keeping a very bright, active child in a less academic environment may be helpful from a social-emotional/executive function development perspective, but may also exacerbate undesirable behaviors, because they have even less to engage them, which forces them to create additional ways to keep themselves engaged, many of which may not fit into the classroom expectations.
That is, keeping him in another year of preschool may make the behavior worse, instead of better.
