Apple just rolled out tvOS 9.1 Beta 2 to developers for testing purposes. This would run on Apple’s new 4th gen Apple TV. This comes just after last week’s Beta 1 update for developers.
For those running tvOS, once you’ve downloaded the developer beta from Apple’s Member Centre, you need to perform a complete restore of your Apple TV in order to upgrade to 9.1. This can be done via a Mac running iTunes with a USB Type-C cable connected to the Apple TV.