It's definitely weird and apple must fix this. This is the complete opposite side of what they claim.
1. This is a Developer beta. Its sole purpose is for developers to test new API's in their own software. Nothing more.
2. Apple has said the release version with have better battery life.
3. No 3rd party app is currently optimized to run on iOS 9 so one or more apps could be causing trouble
Anyone who is experiencing battery issues should test their device in a controlled environment with a fresh install and no 3rd party apps installed.