Yes, I'm fairly sure the fan must be removed first.

There's a special tool that can reach down between the radiator and fan with a stubby socket driver that allows you to remove this screw without removing the radiator.

It's such a tight space that it would be almost impossible without that tool unless you pull the radiator first.

Unless the coolant is literally pouring out of the pump, you can certainly drive it 10 miles or so. I once drove the SD 400 miles with a leaking pump. Just keep an eye on the coolant level.