Apple has released the iOS 9.0.1 update to fix the known bugs in iOS 9. The update is around 35MB in size and is available to all users globally. This release it all about fixing older bugs, so do not expect anything new.
To check if update is available, go to Settings -> General -> Software update and manually check.
- Fixes an issue where some users could not complete setup assistant after updating
- Fixes an issue where sometimes alarms and timers could fail to play
- Fixes an issue in Safari and Photos where pausing video could cause the paused frame to appear distorted
- Fixes an issue where some users with a custom APN setup via a profile would lose cellular data
If you faced issues with iOS 9, you should update now and see if your problems have been resolved.
iOS 9 saw fastest adoption with more than 50% are already running on latest version of iOS. But many users reported multiple issues. This is the reason, Apple pushed this update in just one week after releasing iOS 9.