What is the cutoff(turning 5) for kindergarten?

The school district we live in requires to be 5 by September 1st to be able to start kindergarten. My son’s birthday is 9/22. He barely misses the cutoff. He is 3/going on 4 in a couple of weeks. He is starting preschool(3 year old’s class) and already I see the difference between him and most of his classmates. There is just so many differences between a 3 year old and a 4 year old.

I know this is a small issue but I’m concerned he will be bored and because of that, become a trouble maker.

Anyway, my question is, what is the cutoff where you live? We aren’t married to this school district and are looking to move this year anyway. We need a fresh start somewhere new.