Not necessarily. Remember that cats were worshiped in ancient egypt, even though cats are less inteligent than humans, even the human slaves and servants the egyptians exploited for their civilization. If inteligence came into the figure, then slaves would be worshiped ahead of cats, but they weren't.
The closer the egyptians came to monotheism was at the time of the reign of Pharaoh AKhenaton, when they worshiped the Sun. However, the sun is not inteligent, but rather a non-sentient being.
Pagan peoples worshiped gods that were personifications of forces of nature. See my answer here. They worshiped them to gain a little control over their mortal lives, since they were under the influence of mighty forces they could not control.
Even the egyptian cat-gods were forces of nature, in a sense. Mafdet was a goddess of justice and Bastet was a goddess of war. Cats were only divine in that they participated in Bastet's identity, not the other way around.
For the feline monotheism to kick in, the cats would have to convince the egyptians that cats (and only cats) were able to control the forces of nature they feared... the Nile floods, the harvests, the astrological influence of the stars... So, only by appeasing the cats, would the egyptians be able to survive.
In my opinion, the cats' best bet would be to convince the egyptians that they were masters of the Underworld, since that claim could not be falsifiable and they wouldn't need to know a lot about astronomy or meteorology.
The other way would be for the cats to become rulers of the egyptians. Remember, the Pharaoh was worshiped as a god.