I do it with every beta, and I have since iOS 3's beta on the good ol touch.
Yes, I know you're not supposed to use it as your main iOS version, but the features are so fun its hard to give up. Besides, if I can make it through the first few iOS 7 betas, then I can make it through this one.
So, who's being stupid like me and using iOS 9 for their main OS?
I've been using it on my iPod Touch 5th gen. Works pretty well.