When they don't have a great sleep, it's very frustrating! I feel for you!

I do think the CIO method works but a typical nap here is 2-2.5 hours so I am like you, there is no way I'd leave a crying child in their quiet area for that long. I don't think too many parents would be happy with that length of time either. If they are awake but quiet, it's a different story.

How long have you tried to let him CIO in the past? If he's napping for 45 mins, I'd be inclined to leave him for 15-20 mins and see if he falls back asleep. If he doesn't, I'd get him and have books or wooden puzzles for him to quietly play with until nap is over. Very little talking to him though so that he doesn't sleep shorter periods in hopes of getting up and having fun.

I'm a firm believer that we need a kid free break but I don't feel 2 hours is needed if a child is up and crying. Each to their own though, you will find what works best for you and the children currently in your care.

Hope he starts to sleep longer for you!