They can't stop you but they can limit your options. In this state (CT) and many others they effectively limit public school employment to teachers with state certification. The private school route is the remaining option and, since money is not the objective, it's an option I will pursue.
Or do what you need to do, say what you need to say to get the cert, then do what you want!
Ugg Conn. I left there over 42 years ago. Back then the liberal schools wouldn't allow military recruiters. I skipped school one day in high school and met a recruiter, playing pool. He groomed me for a 30 year career in the military, with no thanks to the liberal school system in Conn. All those southern schools that had ROTC programs in high school got an automatic promotion, making it almost one year ahead of us. So much for career day in Connecticut.