Mentioned to the below responder, but you should give this a try if you're on a family plan, I heard it helps with that problem: https://www.spotify.com/us/kids/

There's not Desktop version for this though, right?

Yeah, same here. Spotify should offer a 'kids' account with every premium subscription, the way video streaming services do.

The family subscription actually does! https://www.spotify.com/us/kids/