Yes, this is pre-installed.

The YouTube application is installed natively on the player

Yes, it works, but it's not really recommendable: the screen is very small and the operation is rather cumbersome. I only use the device to listen to music via the Walkman app plus Spotify from time to time.

Hi weissabgleich78,

yes, you can use YouTube on this player.
YouTube is installed on the player at the time of purchase.
You can find more information on our support page.

Sony Europe