I'm using iOS 9 on my iPhone 6. I've heard this is related to app thinning but apple should seriously consider making app thinning an option to be chosen by the user. I can no longer download updates or apps on my phone because it doesn't back up to my itunes. I learnt it the hard way when i restored my iPhone and realised i had to download most of my apps again. I dont really have a good bandwidth so i'd choose transfer purchases over App thinning. Seriously this is really annoying apart from all the annoying bugs and lags on iOS 9.
Please help!