Personally- my husband still has his wisdom teeth with no issues. Mine came in wrong so I had to get the 2 pulled. For some reason my mouth only produced 2.
I had braces. My mom felt strongly about me having good senior pictures. The sooner the better. I had min. problems, but honestly my only big problem was the sometimes comfortablenesses of them. So many 'famous' people are getting the, and they have such 'cool' doodads like colored rubber bands that its becoming more and more fashionable to fix ones teeth. Though I am sure they won't put anyone in headgear anymore. I hope that is a thing of the 80's. I was lucky I didn't have to wear one, they had some great retainers in the late 80's/early 90's which is when I had them.
If someone wants to bully your son they will find any reason for it.
I had a good set of friends and braces were a part of general life to a point that I never had problems. I think the funny way my mom dressed me caused most of the problems. :) I was a nerd in middle school to blossom into a more self confident high schooler.
Ask your son to start looking at people with braces at school and see if they are getting treated badly for the braces. This might help gage the feelings at his school. But, in the end, he will have some great looking teeth by the end of the ordeal. I still get compliments on my teeth from time to time.