So I've not gotten hold of the Genesys Core rules yet but it seems to me the basic rules are more suitable for younger players than D20 for instance. Besides my kids aren't into the Fantasy setting, but I did think there may be some kids campaigns made already for Genesys. Can anyone recommend any?

What are your kids into?

Check out the list of community created settings and choose one that suits their fancy?

There's a RPG called "Kids on Bikes" as a setting that could be applied to Genesys real easily that could be interesting for kids.

Think of all the movies/TV of kids on bikes: Stranger Things, Goonies, etc. If that's what you're looking for, then, yeah, it could work great!

It hasn't come out yet, but Ghostbusters: Afterlife looks like its in the "Kids on Bikes" genre. I made a Ghostbusters setting (link above) that could work really well for them. You might want to "up the Fear" dice for kids though... or maybe you've got some steel-hearted kids.