Crossfit requires high levels of neuromuscular strength, endurance and memory. I’ve seen a dozen trainers or conditioning coaches put kids through crossfit workouts.
They often have a hard enough time doing a burpie/squat workout, let alone with weight and for speed.
I’d argue that for k-12 the kids need to learn the basics and build upon that.
For that age simply get them into starting strength programs- if a small number of them display great drive and proficiency then put them into crossfit.
Our industry doesn’t oversee programs in this manner. It is unregulated and left up to the integrity of the individual person (s) to be responsible, educated, and hopefully intelligent enough to stay within their scope of practice and be able to execute and design a sensible workout that is beneficial to it’s participants.