Using an iPhone 6  with the iOS 9 beta gives a score 1600.06 points on the Basemark  OS II 2.0 benchmark almost a 100 points more than the iPhone 6 with iOS 8 under the bonnet. The iOS 8 on iPhone 6 scores 1504.08 points meaning that the new OS speeds things up by as much as 11 percent.

The  Basemark OS II 2.0, is a system-level All-In-One benchmarking tool designed for measuring overall performance of smartphones and tablets. It works across platforms including Android, iOS and Windows phone 8. Snapdragon 805, is the fastest SoC in Android space.  It scored 1321.24 on Motorola XT1254, Motorola Droid Turbo for Verison. Galaxy Note 4 (LTE Cat 6) international version also powered with Snapdragon 805 scores 1254.29.  It looks like the Snapdragon 810 will score more than its predecessor and is faster than Apple's best offering. 

We have no idea when Apple plans to reveal its new iOS.  It is possible that it will happen with the new batch of iPads that might launch this spring or it will be introduced in June at Apple WWDC Apple Worldwide Developers Conference that usually takes place in June.  This will mean that it will ship with the new iPhone in September 2015.