My kitten is cream and gray and has deep blue eyes with red pupils. Should I worry?

I'd watch out for possible deafness. There is a gene (white-spotting gene) that makes the eye blue, and if it affects the ear as well, it will make the cat deaf. Given the color combination you have, it's possible that your cat has this gene. It will only matter if the gene is "on" in the ear, and there are other genes that can make blue eyes.

As always, if you are in doubt, talking to your vet is a good idea.