Downgrade from iOS 9 to 8
How to delete the iOS 9 beta and reinstall iOS 8
In the previous article we looked at how you can download the iOS 9 beta and check out its new features. But what about if you decide that it’s not for you? Here we reveal how you can erase the beta and reinstall iOS 8. For the purposes of this article we are assuming that before you downloaded the beta, you made a backup of your iOS device.
Put your iPhone or iPad in recovery mode, and then restore it.
If you use Find My iPhone, enter your Apple ID and password after the restore. This will activate your Apple device. (If you can’t get the iPhone or iPad to restore successfully, check Apple’s relevant support page for solutions.)
Plug your iPhone or iPad into your Mac, open iTunes and select the option to set it up from the backup you archived earlier.