To answer the question, yes, there are definitely several things called Satanism that exist, with serious adult members.
I’m no expert, but I’ve seen, read about, and heard about various sorts of Satanists.
For example:
* Angry kids (mostly but not entirely) poorly raised by Christians, who express their anger and rejection by identifying as Satanists and possibly sacrificing some animals or something. (Often inspired by Christian and/or Hollywood exaggerations of Satanists as terrible villains, they act something like that out.)
* Intellectuals who subscribe to a new religion called Satanism which is very humanist and tends to speak out an demonstrate against Christian hypocrisy and issues relating to separation of church and state. (e.g. http://deadstate.org/satanic-temple-argues-that-missouris-extreme-abortion-laws-violate-their-religious-freedomfbrefreshforce/ and http://time.com/3972713/detroit-satanic-statue-baphomet/ )
* People into a spiritual relationship with Satan, and/or a magical relationship with Satan.
* People who are mainly just into the style or shock value of Satan.
It seems to me that the above behaviors are pretty distinct and generally don’t really overlap in the same people. But I’m probably doing some people a disservice by sharing my imperfect knowledge and understanding.