I sync/backup 6 devices to iTunes on my Mac (not iCloud). Every once in a while I used to delete the apps in iTunes in an effort to clean things out; I don't need to back up apps that have been deleted on various devices. When I did that in the past, I would re-sync each device and "put back" the apps that were actually used. Yesterday before updating to 9.0.2 I removed all of the apps in my iTunes library in one of these periodic clean ups. However, when I went to back my iPhones up, instead of getting the usual message about purchases on the devices not been gin my library, it just backed up like nothing had changed. I started to sync, but cancelled the process not knowing if it would delete apps (and app data) off my iPhones. So has something changed? Is it no longer necessary to keep apps installed on my devices in my iTunes library when backing up to iTunes? Is it safe to sync (i.e. music) without fear of losing app data?