If you think a second pet will help alleviate loneliness, boredom or behavior problems with your resident pet, think again. If you don't have time to spend with one cat, you surely will not have time to spend with two. Many cat owners end up with two bored and misbehaving pets instead of one. Furthermore, a second pet will not necessarily provide your cat with the companionship you have in mind. If you are willing to put in the time, patience and expense of a second pet, then take a look at your cat's desires.
Cats are by nature, highly territorial.
A cat, especially an indoor cat can become extremely stressed if he thinks his territory is being invaded. Unless a cat has been raised with other pets and has been socialized with them, he will not readily accept them and will most likely be happier by himself. If this is your cat, you should seriously reconsider your plans. You're convinced you have the time, you want another pet, and you've decided your cat will definitely enjoy a companion. Unless you already have experience with them and knowledge of their needs and behavior, you must be willing to do some research and gain at least a basic understanding of rabbits.