iPhone 6 iOS 9.0.1 Update: 10 Important Details

Still No iOS 9 Jailbreak

There is no iOS 9 jailbreak and it's still not clear when one will be released. If your iPhone 6 is jailbroken, don't install iOS 9.0 or iOS 9.0.1. 

It looks like jailbreak devs will release an iOS 8.4.1 jailbreak so you'll want to be on the look out for that ahead of the iOS 9 jailbreak release.