Wow. I can't imagine picking up my iPad on iOS 9 and not having it instantly start to get warm. Within 5 minutes it's noticeably warmer then it should be.
Did you try a DFU mode restore on it? That has help rid the bugs for me on my iPhone for the most part (minus the battery).
Meanwhile, watchOS 2 beta 1 is horrible. I wish I could revert back. Oh well. Its what I get for being a beta user.