iPhone 6s iOS 9 Update: 10 Things to Know After Two Weeks

Downgrade to iOS 9.0.1 Still Open

If you aren't liking iOS 9.0.2 and its performance, you can drop back down to iOS 9.0.1. However, you can't drop back down to iOS 9.0 or the iOS 8 update. 

Apple typically signs off on updates for one to two weeks after a release so it could pull the plug on iOS 9.0.1 at any time. Keep an eye on it as we move deeper into October.