The grocery in Cupecoy is open, yes, and is a smaller Carrefour. You also have the market in Maho, as well as the big former Grand Marche at the roundabout by Mark's, which is now a Carrefour. There is also the Market Garden, at the corner of Billy Folly Road.

By the way, with regard to grocery bags, I would bring some, as I'm not sure, but I think no one supplies them free anymore. A wad of grocery bags don't take up any room in suitcase.