Satanists use the upside pentagram in some symbology, but this is a right-sided star used in Wicca and Paganism.
While I’m not defending either of those cults, to say that the pentagram is a sure sign of Satanism is like saying that middle eastern guys with turbans and beards are Muslim. Many of them are Sikh and those that are are very, very opposite of Muslim.
Wiccans and Pagans not satanic. They are more Druidic than anything.
That said, this cat is likely wearing it as a style or is a Wiccan. I know plenty of Wiccans and they are all bad, bad people.
“You shall not suffer a witch to live.”
I have some news for you. If it’s not of God, it’s evil. Wiccan, druid etc, it’s all a form of Devil worship. It’s pretty black and white.