Hi and welcome! The good news here is that your dog is extremely unlikely to have any problems while you are gone and I am going to place a wager that within two days of boarding, he will be eating whatever he's given

. That's because dogs, especially puppies, can be very smart and manipulative and 99.99999% of the time, this kind of food merry-go-round is the dog learning quickly that it can get lots of attention, interaction and interesting new foods and treats simply by refusing to eat! It's one of the most common puppy questions (along with housetraining issues!) we've had on this board over the many years we've been here.
Managing this will take a little will power -- from you! This is what you do:
1) decide on a good food that satisfies your dog's nutritional needs
2) place the food down for your dog for 15 minutes and then IGNORE your dog. Do not look at him, don't move the dish, don't talk to him, don't cajole him and do not hand feed him.
NO interactions!
3) after 15 minutes, without making any big deal of it or saying anything, just lift the dish and put it away until the next scheduled meal. Do not try to cajole him to eat a bit more, do not offer a single thing to eat until the next scheduled meal, no treats, nothing. This is critical!
4) at the next scheduled mealtime, repeat as above, offering 15 minutes til the food is put safely away. No cajoling, no looking at the dog or talking to him during that time.
5) if he doesn't eat at all: fine!! A dog, especially a pup,
will not starve itself. A pup especially at 8 months can easily miss a few meals, even a day or two of meals. Believe me: your dog WILL eat eventually. And when he does: you continue as above. Don't make mealtimes a big deal. The food goes down, the food is left for a set short time, the food then goes away. The dog eats when it is convenient for you and what you wish to feed.
This WILL work. I've had to use this approach with so many dogs when I ran a rescue, including dogs that were surrendered by owners who told me I had to hand-feed. That's just the dog very effectively training its humans

. Our current puppy, a Great Pyrenees/ Pyrenean Mountain Dog, did exactly what you describe and he sometimes just refused to eat. But he's now a good health size at 9 months and eats normally. It was a real headache for a while so I know how frustrating this can be. And hard to not want a quick fix, or try lots of new foods, etc.
I am guessing your dog will find it has a choice to eat or the food goes away when boarding, and also will realise he isn't dealing with you but a stranger. So he'll re-set, eat perfectly normally, and this will get you set to continue with this new approach rather than having to come up with ever new things. But start getting him on this new track right away, and I'll bet things are pretty much fixed within days!

As he's a health happy little fellow right now, you don't need to worry about his health at all if he is stubborn and holds out on eating for a day or two. Let that be HIS choice! He'll learn quickly that the games are now over and he needs to eat or go hungry.