Hitting vault is high priced. I’ve purchased many high priced programs and can say 100% they’re never worth the money.
I do not recommend Richard Schenck’s program. The price is right but preview his content for free by just googling his name. Put aside his my way or the highway personality, I don't believe his teaching is well suited for young girls especially. I would lean more towards Justin Stone or Hitting Vault guy.
From what I've seen, the Patreon sessions are a deeper dive into the material than most of what can be found elsewhere. That said, I also wouldn't call Richard's material a "program" in the sense of "start here and follow this progression of drills".
For a young kid I would find programs/drills which focus on getting to a good balanced position to hit from. Part of the feet together drill from Stone (posted above by @Rolling Hard ) is about that. Doug Latta talks about that as well. Without that everything else the body wants to do is a compensation for the lack of balance. Some kids have no issues with this, others do
Ok, I say if you start here and master just this one drill and listen to this other video on approach you would be well ahead of most hitting coaches and dads.