In addition to iOS 9, Apple on Thursday released the fifth beta of watchOS 2 to developers. The update can be downloaded and installed over-the-air using the Apple Watch app, but  be careful because it requires your iPhone be on a recent iOS 9 beta and it's very difficult to downgrade.
Today's beta 5 comes a little over two weeks after beta 4, which activated Apple Pay and fixed issues with Apple ID in the Messages app and the Activity complication. It also arrives roughly two months after Apple first unveiled watchOS 2 during its June developer conference keynote.