Most wouldn't agree with me, but if a pup is being a brat in the kennel I sneak up and thump the top of it with my fist. It startles them into silence which you can then praise for.

I've never had a dog become scared of me or of the kennel because the dog doesn't see me making the thump on the kennel and they seem to associate their screaming at the top of their lungs with the scary noise. Not just the kennel with the scary noise.

I hope that made sense.