Reply #9: If it were me, and I was putting my usual tonnage of books [View All]

[Warpy]

or sound equipment on the shelf, I'd probably spackle the hole and redrill the right size to accept a screw either half an inch above it or below it.

You can fill the hole in the stud with plastic wood, but if you didn't drill a deep hole, it really doesn't need to be done.

I wouldn't expect plastic wood in a hole to hold a shelf with the kind of weight I generally put on them.

If, on the other hand, you stopped drilling as soon as you hit the stud, you can drill the stud to accept the wood screw, hang the shelf, and not bother spackling the hole until you decide to move and have to repair the wall.