The Cat Lord has a long history in D&D.
The Cat Lord first appeared as Meerclar, Lord of the Cats (based on a character in Michael Moorcock's Elric stories) in Supplement 4 to the Original D&D game. (3 brown books/OD&D). The Cat Lord was described as:
A giant sabre tooth tiger, standing 20 feet tall and 30 feet long...He
is able to sense anything within the range of any feline, and can call
on 1-100 tigers and 1-50 lions to do his bidding. This being, when
called, will not appear himself; he will work through a cat on or near
the area. If he is forced to come himself he will kill the caller. (Gods, Demi-Gods, and Heroes, TSR, 1976, p. 55)
As you can see, worship of the cat lord had its benefits, and its hazards. He was one of a number of Master Types (Others being Lizards, Snakes, etc)
These beings live in other dimensions called half-worlds. In these worlds every creature of earth has a ruler which is the most perfect specimen of his type. They are all neutral in alignment
The Cat Lord reappeared in the Monster Manual II for AD&D (1e) and was generally considered a "quasi-deity" at the time.
He was used in Greyhawk some most notably in Gary Gygax' "Gord the Rogue" novels, where Gord has an affinity with the Catlord (they're related, actually) and eventually takes on the mantle of Catlord. I am not sure I can in good conscience recommend that someone read those books, as for all his merits Gary's prose skills are somewhat off-putting, but there is a good bit of lore detail, including the idea that "Cat Lord" is a title passed on from near-deity-level badass to another, in them, especially in Saga of the Old City. Here's a writeup of Rexfelis the Catlord from the Greyhawk days.
Animals Lords are powerful creatures of neutral good alignment that live on the Outer Plane of the Beastlands. In the game, each animal lord is a humanoid being, powerful like a celestial paragon or demon prince, that represents all animals of its chosen type. For example, there is a Mouse Lord, a Lizard Lord, and a Hawk Lord. The most well-known animal lord is Rexfelis, the Cat Lord." - Wikipedia's List of Greyhawk Characters
In Second Edition, the Planescape Monstrous Compendium has a female Cat Lord, as one of a set of animal lords.
3rd Edition: Tomb of Horrors Complete, in which he's a unique outsider.
Anyway, in all the classic depictions, he or she is strongly aligned with the forces of Neutrality, and pays little mind to the human realm, mainly being all about the cats. He's only known to be friendly with one other deity, Xan Yae, a Neutral monk goddess. As such there are no churches or rituals or whatnot - his worship, even among felines, is "more of a partnership."