Not many active members of the Church of Satan, probably even fewer active members of its offshoot the Temple of Set. Numbers, not surprisingly, are hard to come by.
Neither believes in Satan as an entity. They also generally do not believe in God, holding both God and Satan to be created by, and aspects of, every individual. “Satanism” is the worship of–actually, more like embracing of–the desires, drives, lusts and dreams of mankind without constraint by societal or religious morality.
But LaVey pretty much grabbed the name as a way to fuck with the mundanes, IMO.
They’re Crowleyan in their dedication to “do as thou wilt,” and are pretty much the crazyass Objectivists of the theological world.
I’ve known several, mostly dabblers, but none with kids.