Is this a public school? If so, can you arrange to have an aid or a para with him for the rest of the year? Obviously it won't solve any underlying issues, but it might give him the opportunity to complete the school year with less risk of incidence occurring.
If it continues to persist with an aid/para and the playground triggers 90% of the behavior, is there anyway that you can have him sit in the office during recess time? I realize that getting his excess energy out is important for him, but I can see the most important issue right now is finishing out the school year safely and until you have a game plan to deal with the disruptive behavior you might want to just put a temporary catastrophic plan in place.
I wish I had a better solution for you. Good luck.
