I wear a size 9.5, what size should I get, 9 or 10?

These boots seem to run a little large. My grandson wears a 10.5. I got him an 11 and then had to return for a 10, so I would say a 9 should fit.

Why are these boots $20.00 cheaper on amazon than muck's own website? are they the same quality, the same boot?

Because it’s not nor was ever a muck brand boot. Maybe read a little bit before popping off. But I’ll help you out. So this brand style what have you boots was started by the former Muck Boot Company founder and owner, Jim Donohue. Now Read that again. He later on sold out Too another company years ago & then began making this style of boot. so yeah they look like muck brand because that was his idea too. And mucks are crap ever since Rocky clothing & boots bought out the company. Since 2014-15 the boots do not hold up like a muck boot from 2000. They are having everything done in China. Dryshod is an American based and American made product. Anyways your welcome. But sorry you won’t see a Dryshod boot on the muck Boot Company website. 😉

I'm a delivery driver and I go down a ramp are they slip resistant

yes they are. I wear them on the ramp when Im putting the boat in the water as well as in the garden on wet grass. Im very happy with them. Theyre not warm though so you will need very thick socks or get them lined if you plan to wear them in the winter.

Why is the men size on these boots smaller than the women's? Im a 9 woman and I'm trying to find the correct size

Men’s sizes are smaller than women’s. Usually if a woman wears a 9, then the same shoe for a man would typically be 1-2 sizes smaller. I used to work in a shoe store. It’s weird. Hope that helps?