Apple has just released the second beta of iOS 9 for developers. You may also be installed without developer account, but this longer downloading the corresponding ipsw and updating from iTunes. This new beta of iOS 9 are expected to focus on improving performance and general reliability, but not download new functions or some other visual changes are included. It will gradually be around until the final release is expected to be in mid-September.
As expected, the main improvement has brought this second beta of iOS 9 is the solution to the problem at the first beta that made the iPhone battery is saw significantly affected since this could not last a single day due to excessive consumption.
iOS 9 beta here: Download iOS 9 Beta 2 And Install On iPhone,iPad, iPod touch