Install It If This iOS 9 Problem Was Annoying You
If you weren't able to turn off the setting for app cellular data usage in iOS 9, and we spoke to several people who were unable to do so, you'll probably want to download the iOS 9.0.2 update.
iOS 9.0.2 "fixes an issue with the setting to turn on or off app cellular data usage." We've been using iOS 9.0.2 and the setting hasn't been giving us any problems. If it's giving you problems in iOS 9.0.1 or iOS 9.0, and you're frustrated, you'll probably want to make the move to iOS 9.0.2.