I can't be sure. It has no desire to be named, you see. But the details certainly fit, particularly the wards against it and being killed by a cat.
I think that it must have taken different names at different times. Perhaps it was 'Apep' then, or took on that moniker for a short while. The only major difference I see, however, is the universal hatred for Apep. He sounds like a bit of a 'devil' figure, or the devil was we think of him in the last few hundred years, the one everyone blames when things go wrong. I think it's been a bit better at tricking people into worshiping it than that, at least in recent centuries. That doesn't mean no one was worshiping Apep on the sly somewhere, though.
Some of the details of this one also seem to fit. The intense worship for such a short period of time. The golden sun. The near madness of its followers, and then the revolt of the next generation who returned to the older gods.