Audiobus: Use your music apps together.
What is Audiobus? — Audiobus is an award-winning music app for iPhone and iPad which lets you use your other music apps together. Chain effects on your favourite synth, run the output of apps or Audio Units into an app like GarageBand or Loopy, or select a different audio interface output for each app. Route MIDI between apps — drive a synth from a MIDI sequencer, or add an arpeggiator to your MIDI keyboard — or sync with your external MIDI gear. And control your entire setup from a MIDI controller.Download on the App Store
Audiobus is the app that makes the rest of your setup better.
iOS 9 can't back up apps anymore ?
Is this the case for anyone else ? I tried with iTunes and transcopy and the apps weren't being backed up like I was able to do pre iOS 9. So, it looks like restoring a device from a backup requires the apps to be downloaded again ?
These links shed some light on the issue: