It appears from the picture that the garment has pockets. can you confirm that is the case, if so how many, and are they zippered?

It has one "pouch" style pocket (like most hoodie sweatshirts have) that is zippered on both sides.

Is it a sweater or jacket? I can’t tell by the picture but description says jacket. Another person called it a pullover sweater

In my book, it's not a jacket because it doesn't have a full zipper. And I wouldn't use the word sweater for anything made of fleece. I'd call it a pullover.

What size for a man who is 5 foot 9 and weighs 179 lb

Maybe the sizing has changed since 2020, because I am also 5'9" (but a little lighter at 160lbs) and I first bought a large. It was too long. Went several inches below the waist line, and the sides were very loose. I exchanged it for a medium and that fits perfectly.

what is a closure closure?

i think your talking about Zipper closure. the zipper opens at the max 1/4 of the total fleece length. when the zipper is pulled all the way up the fleece is fulled closed hence fleece is a zipper closure.