I posted this before in another thread, as a developer I am working on an app which uses background services for location, BT and sending message to the watch. Even after the app was terminated these radios seem to remain on and working full power. After deleting my app and rebooting the battery use went to normal. I don't stream music and haven't found using the music player effected battery use any more than normal.
What I suspect is the iOS 9 Beta (version 5) is leaving a radio operating at full speed even when apps are terminated. My suggestion is to delete a suspected app and reboot the device to see if that fixes it. Send a bug report about the battery drain.
Something in the OS isn't doing it's job.
I agree with your statement. Something is not cleaning up right with the apps and I am glad you're trying to take care of it. However, DeNA's FFRK app itself is really bad. If you use it on an Android device it's battery drain and performance is even more abysmal as it appears they're doing everything on the UI thread. Also considering that FFRK shouldn't really be doing anything in the background (it's just a farming type game anyway) the fact that it sucks up the battery leads me to believe that the apps are not suspended properly or they somehow annoying marked their app to run in the background.