I think they will be much happier at home with someone checking in on them than at a kennel. Ever since my parent's health got too bad for them to pet sit for me I've started taking my dog to the kennel and leaving cats at home. The longest I've left Ripley alone (with someone checking in) was 5 days and he did just fine. Since I've added Jazz and Scout to the family I've only left them once for a few days but they did well. I had someone come once a day to feed and play with them and scoop litter.

Try not to worry too much. They will be okay.