It will come back in an hour and a half. But, it will drift a little because of atmospheric drag and sunlight pressure so it won't come back exactly to where it was set adrift. It could hit the ISS when it comes back.
Are you kidding, Mr. Whale? The bolt is probably co-orbiting with ISS, for the most part. It's not like it stopped dead in space, waiting for the station to take a lap.
It will eventually drop out of orbit.
Does that mean it could act as a harmful high velocity projectile and penetrate the ISS?
That's not good.