Out of iCloud Storage After Updating to iOS 9

If your iOS device suddenly tells you, you have run out iCloud storage, shortly after updating to iOS 9, here is the possible reason! It seems that in iOS 9, Apple is automatically switching on iCloud backup for all apps - by default (if you choose to activate iCloud), even if before hand you had manually switched off certain apps - like a large photo library, which may be bigger than the allocated 5GB of free storage. 

Users may need to go into the settings and re-adjust their iCloud backup settings to free up some space. Or, if you want to continue to backup all the data on your iOS device(s), you may need to purchase a higher iCloud storage plan. 

To adjust what's being backed-up to iCloud in iOS 9, open the Settings app, tap General, then Storage & iCloud Usage, and under the iCloud heading tap Manage Storage. Choose your device and then you can manually adjust each app's backup setting.

You can learn more about iCloud on the Apple Support webpage.