Remember in Japanese it is important to use the right honorific Generally, "-san" is used for a wider range of animals, while "-chan" is reserved for pets and animals considered cute. "-Kun" is less common for animals, but can be used for certain pets or animals that are seen as having a boyish or playful nature
For cats of course one uses Sama (様) or maybe if it's your own personal lord and master Tono (殿) / -dono (どの) and kittah likes you a lot. Otherwise stick with Sama.
