(As a precursor- none of the kids I taught had a keystone, so I have no knowledge on thise)
+1 for the rpr overall for double digit aged kids as stated above.
I was a 4h shooting sports instructor for years, and depending on the kids size, there are some great choices nowdays.
For a small kid- I don't recommend the cricket- the pull the bolt back feature is just poor shooting mechanics- a much better early shooter is the savage rascal (think preschool kids).
It's hard to beat the classic 10/22 for- well everything. Learning to load, positional shooting, function, etc. For an all around gun. Everyone should have 1 or more.
A more accurate and "deliberate" version of the 10/22 is the rpr. There are some bad ones (all built around covid time from what I saw) but the majority are great shooters.
For the serious kid who catches the fever we get that Will always keep them poor- there is the tikka, kidd, cz.
And, if you secretly hope they won't stay in it (and you'll end up with a fun plinkster and want to blow a little of their college money), the christensen arms ranger, the vudoo, and rimx. ( all of which will be limited more by the cartridge, and especially the shooter than anything else).
If you need ideas for doing fun kids games/ etc once they've gotten settled with safety and start hitting things, let me know.
