Familiarize With the iOS Downgrade Process
You can still downgrade to iOS 8.4.1 from iOS 9 if you don't like the new update. That loophole won't be open forever though.
We think it's important to get familiar with the downgrade process, even if you wind up sticking it out on iOS 9. There should always be a downgrade option after every iOS update and this way you'll be prepared if you wind up hating iOS 9.1 or another upcoming upgrade.