Fenrir is not a god.
He's a devouring beast who is an enemy of mankind and kills the god who ordered the world. Why would you want to worship that?

I can see why you might be interested in his role in myth and so forth, but actually honoring him would not be wise, in my opinion.

You, of course, are free to do whatever you wish. But consorting so closely with one of Loki's progeny will likely reinforce your self described "outsider" quality.