Kennel cough in cats or dogs is caused by Bordatella, it can be transmitted from dog to cat, and vice versa. It may or may not be bordatella, so a vet visit will be in order. Kittens also sneeze sometimes, with no explanation other than cats and kittens sometimes sneeze. Is he/she showing any other symptoms now other than sneezing?
If it is Bordatella infection, the vet can easily swab to test for it, and put him or her on the antibiotic that is right. Often times it goes away on its own, if it is indeed bordatella infection.