How soon is your dog due to go into the kennels? It could be that they are wary of the live vaccine given for kennel cough, when I managed kennels we would not let people bring in dogs that had been vaccinated for kennel cough within the two weeks prior to the kenneling, as the vaccine gives them a mild form of kennel cough, so they then build up immunity, and go home ok, but leaving other dogs infected.
There may well be other vaccines available now, but I have never had one done, especially as they only lasted six months. Most kennels ask for the other vaccines, but not kennel cough.
Personaly I never vaccinate my adult dogs, they are done as puppies and this has been my policy for 20 years although if there was an outbreak in my area of say parvo, I would have them done for this, or if they were in contact with rats, for lepto.
If my dogs go into kennels, it is they who are at risk, not the other dogs, so it is at my own risk and my kennels are happy to accept them on this basis. It is NOT a legal requirement for dogs to be vaccinated before going into kennels.