Apple released iOS 9 beta today. This automatically gives iPad and iPhone users scope to test the yet-to-be-finished OS. So even if the next iPhone—the iPhone 6S hits marts in September, you can know its operating system well enough.
Perhaps this decision from Apple came about as a safeguard against plausible glitches that it has already faced with its iOS 8 goof-ups. The latest iOS 9 is compatible all iDevices that run on iOS 8 at the moment.
Updating To iOS 9
The iOS 9 update comes for free. However, users will need to perform a device-enrol for the beta software public program. Before installing the iOS 9, it is advised that all current iOS data is backed up from the iTunes program instead of banking on iCloud. Follow this up by a profile download from your iPad or iPhone before updating.