There are still a couple known issues with the beta.
● A user updating to an iOS 9 GM build from a seed build may see duplicate dictionaries in the
definition dictionary list if the user switched primary language, added secondary languages, or
added new keyboards. Workaround: To remove the duplicate dictionaries, go to the definition dictionary list, swipe the dictionary, and tap the Delete button
● Photos app in Simulator does not sync photos from iCloud Photo Library.
Developers can download the beta from the link below...