My daughters were left alone, at home for a hour or two when they were 8. It seemed pointless to drag them along to the grocery store. Shopping is never fun with kids in tow.
My wife or I would make sure they were occupied watching a movie. Our oldest was responsible for watching her younger sister. We’d go to the store, or run a errand. We always came back with a bag of burgers and fries to reward the kids for being good.
They were around 10 or 11 before we felt comfortable leaving them home all day. Summers for example when school is out.