The beta features some new wallpapers, support for Wi-Fi Calling on AT&T (still not functional), keyboard tweaks, Wi-Fi Assist (switch to cellular when Internet is poor over Wi-Fi), CarPlay UI tweaks, and more.
You can sign up for Apple's Beta Software Program at the link below...
Did anyone saw the update final iOS 9 running now on my phone wow this cool by Apple I never had to do anything I saw a message say my phone is update from beta