If your son already loves cats, this is a perfect pet! Suggestions that I have is to make sure that kitty and your son get used to each other. Show your son how to carefully pet kitty. Wait until your son is older for holding the kitten unless the kitten is the type that does not mind your little one dragging her/him all over the place. Another thing is to watch how the kitten reacts to people. Some kittens are not fully trained yet and still need some help. Such as scratching or playing with hands and feet. If the kitten plays with hands and feet, carefully grab the paws and look at her/him and say "no". Then, take the kitten to a toy and play with her/him and also be sure to give it praise when it does play with the kitten toys. Don't yell at the kitten, and tell your son to "be nice to the kitten" if he starts getting too loud. Explain to him that loud noises scare the kitten, and tell him not to hit the kitten, even when it scratches because the kitten will think that you are playing, or will become very frightened of people.
If the kitten is litter trained, be sure to tell your son that the litter box is the cats potty so that he does not think that it is an indoor sand box. lol Having a cat use a litter box might also help during potty training (if your son is still going through that). Also be watchful of the cat food. Some children like the taste of cat food and will try and sneak a few bites from it.
You can also have your son help brush kitty with a soft cat brush. This will help the kitten and your son bond more because grooming reminds the kitten of his mom and kitten-hood.
Be sure to watch out for "itchy" signs too. If kitty starts to itch, comb her/him with a flea comb outside. If kitty has fleas, give her a bath right away!!! Another thing that helps keep fleas away is eucalyptus oil. Mix a few drops of eucalyptus oil with water and spray it all over your carpet, rugs, and furniture. Eucalyptus oil is poisonous to fleas, lice, and ticks and is also not all chemically and is safe to use around children.
Our son was two when we got our first kitten, and now they are best of friends. His cat sleeps with him, plays with him, walks with him part of the way to school, waits for him by the front door when he gets home from school, and even comes running when he is crying. She is like another mother to him.In fact, when she was younger, she tried to teach him how to catch a bird. lol... She totally acts like he is her kitten, and it is so cute! Our other cat just had four kittens last month, so we have quiet the kitty population here. ^.^
Beyond that, enjoy your new addition to the family and have fun!! ^.^
M. *~