He's not trained and ready for underwear if theres a chance he'll poop himself. And he hasn't earned the right to be in underwear yet. Underwear should be an exciting part of toilet training... like the best reward of all!

I would just let the clients know that he needs to be in pull ups for a little bit at daycare to make sure he's solid with all bathroom functions. That's just the way it is.

As far as poop accidents in the pants? I put a bag on my hand and pick up the soiled clothes, turn the bag inside out, tie it up and put it outside the front door. I don't clean poop. I don't have time, I hate the smell, I have too many kids to watch, it's not sanitary for me to be cleaning it.