Jailbreakers beware: iOS 9.0.1 is no longer being signed by Apple.

If you recently jailbroke your iDevice, it’s best recommended that you take extreme precaution when installing tweaks and themes that might cause a jailbreak failure, since Apple is quickly stopping support for previous iOS versions that allow jailbreaking (currently only 9.0.2)

At the time of this post, Cydia Impactor, the best tool to restore devices to their current installed firmware, is still under development for iOS 9, but Saurik is working around the clock to bring it to us.