Apple is in the process of sending out the new version of iOS 9.0.2. The new version come out exactly after the released of iOS 9.0.1. The changes in the new version is they includes a fix that reapir an issue with the setting that turns on or off app mobile data usage.
The issues that prevented iCloud Backup during manual backup and incorrect screen rotation when receving notification are also fixed in this update, the update weighs in at 62.1 MB.
In addition to pushing out iOS 9.0.2, the apple has also stopped signing iOS 8.4.1 and 9.0, which means that you won’t able to roll-back from a more recent iOS version to these version.