Old wire shelving pulled free of the wall and the anchors came out leaving large holes. What is the best way to rehang shelf using same holes?

More then likely best if you don't attempt to use the same holes. How long is the shelf ?

Kill 2 birds with one stone: put 2 x 3's over the holes and they can be the new shelf supports. Mark the studs first so you can make sure they go into them.
If it needs to look 'nice' use a nicer wood, like clear fir.

Don't try the same holes. Find the studs and screw in to them. Get some drywall mud and fill the old holes.