User Manual Cuisinart CSB-400CD Smart Stick® Cordless Hand Blender

No, it's not a USB socket. Rather, it's a cylindrical jack (not a headphone jack). The charging cord and transformer come with the unit box-set.

Not sure what a scratch guard is.... Try reading the details on the item posting, where it says:
5 speed settings
Long, slim 8 3/4˝ stainless steel shaft with large 3˝ commercial - design blade guard.

No, there’s no plastic or rubber guard on the end. I have used it extensively in stainless steel, ceramic, glass, and plastic bowls/pans/containers and haven’t noticed any scratching. There may be some, but not enough to notice without close examination.

It's not a charging station with a receptacle. Rather, there is a plug / transformer unit, and a cord with jack that inserts into the unit. The plug / transformer component is approx 1 "x 1" x 2 ".