I’m concerned that my child may see inappropriate pots in the game (Kiln)

If your child is on an age-restricted account, the game should automatically be enforced into Moderated Pots mode, in which player created pots encountered online will be replaced with generic versions of each pot shape, so if a player creates anything inappropriate, they shouldn’t see it. 

For accounts which are not age-restricted, the game will also ask if this mode should be activated on first launch, and it can be manually activated in the Settings menu under Gameplay by switching Moderated Pots Mode to On