Install It If You Want to Jailbreak iOS 9
Developers have finally released the first iOS 9 jailbreak for iPhone, iPad and iPod touch. The jailbreak supports iOS 9.0, iOS 9.0.1, and iOS 9.0.2. The only iOS 9 update you can get to at this point is iOS 9.0.2. Apple's closed off the iOS 8, iOS 9.0, and iOS 9.0.1 downgrades.
There's a good chance that iOS 9.1 will kill the exploits used by the jailbreak so you'll probably want to make your move to the iOS 9.0.2 update right now so that you're safe.