Yep I am in the US. The "whitelisting" option wasn't exactly easy to find. You have to login to the kids app as an adult, setup a special kid profile, activate that profile, THEN whitelist.

I remember getting pretty frustrated at how complicated it was, but I eventually got it.

Thanks for this! I didn’t even know it existed. I’ve been frustrated that I can’t add my kids to YT premium since their emails are at my custom domain hosted by g-suite. This feature is worth the hassle of setting up gmail accounts and figuring out whitelisting. They have just been sticking to “approved” channels on the honor system which works pretty well, but it’s not perfect.

you've the right to be frustrated, as it's also shame that they made it complicated and this hard to find for the US version of the app.