On OS X I run iTunes (12.2.1.16)
I keep going from iOS 9 beta 3 back to iOS 8.4 due to finding glitches. Because of this I have to keep waiting for ~20mins for iOS 9pb1 to download. Is there a way to download the IPSW so I can doit within iTunes to skip the waiting time?
To get iOS PBs I had to enrol my device by installing a profile. After I done that I then updated OTA via System > General > Software Update.
Best Answer
I would try again with the latest public beta - for many reasons in addition to being a more stable installation experience.
If you have access to a developer certificate/account, the quickest way forward is to log in to developer.apple.com and download the beta build 13A4325c then point iTunes to it for the restore.
Since you have the other method to install the beta - using a signed profile to change the provisioning of the device OTA, you have a longer road ahead.