MUCKUnisex-Adult Chore Classic Rubber Work Boots Men's Mid Soft Toe

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

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

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

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