There is no official YouTube TV Apple TV app, but you can stream YouTube TV on any device running iOS 9.1 or later. This means you should be able to watch all YouTube TV content on your Apple TV using AirPlay. Here's a list of YouTube TV supported devices:
- Android L or later
- iPhone iOS 9.1 or later
- iPad iOS 9.1 or later
- For the best YouTube TV viewing experience, download the latest version of Chrome. (according to Google who owns YouTube)
- Stream with Google Chromecast, Chromecast built-in TV, and Android TV.