Unity iAD Crashing in iOS 9

I have an game that's been on the App Store and running on all devices running iOS6 through 8.4.1 with no reported crashes.

During the iOS 9 Betas and including the Final iOS 9 release, my game is crashing when showing/closing iAds -- both interstitial and banner:

1. Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason:'accessing...

Unity iAD Crashing in iOS 9