I have discovered in one of the first betas that after a clean install turning on my iCloud Photo Library (around 37GB) with Download and Keep Originals enabled takes up almost twice the storage as it normally should. I connected it to iTunes and it shows around 60GB's as Other. This problem persists with yesterday's (13A344) release as well. The only solution for me was to downgrade to 8.4.1 where downloading originals occupies the correct amount of storage, and then update to iOS9 afterwards. Anyone noticed the same?