I think you handled the situation quite well. Remember...you can use DB on him, i.e., give him plenty of space and time. Right now, he's clearly unhappy w/his school and he may think that if he acts out, you'll eventually give in and allow him to go back to the old school.
Remember to breathe and don't let him see you sweat.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
