iOS 12 beta 9 is now available for registered developers, who can download it on their device by going into Settings > General > Software Update. It's also available through Apple's Developer Center on the web. There's no update for public testers in the Apple Beta Software program yet, but it should appear in the next day or so.
Apple released iOS 12 beta 7 one week ago, but the update was causing performance issues for some and so Apple pulled it and then released iOS 12 beta 8 a few days later. iOS 12 beta 7 also removed Group FaceTime. Apple hasn't said why it pulled Group FaceTime from the beta, but it did say that the feature "will ship in a future software update this fall".
The update to iOS 12 includes many new features. Grouped Notifications will help to declutter your lock screen by grouping together alerts from the same app, while Siri Shortcuts will help you perform actions in third-party apps using Siri. There are four new Animoji, too, along with the ability to create your own Animoji using the Memoji feature.
iOS 12 will launch to the public this fall.
Apple today also released watchOS 5 beta 8 to developers. This update is available in the Watch app by going into General > Software Update. It includes features like Walkie-Talkie push-to-talk with other Apple Watch users, auto workout detection, and Activity Competitions. Like iOS 12, watchOS 5 will be released to the public this fall.