It's only a short train ride (15-20 minutes) to downtown Amsterdam or Haarlem. I would think you'd have an easy 2-4 hours to see some local sights. I would only wonder about how much time to leave for getting back through security when returning to the airport. Also if you check RS' guidebook, there's some museums and shopping inside the airport itself. A meal and a museum might be just the thing since you'll be arriving jet lagged anyway.
We'll be flying into Schiphol ourselves late September and our plan is to kill some time by not being in a hurry at the airport anyway since we can't check into our hotel until the afternoon. We usually try to stay up until late afternoon by walking around and that could include the airport mall/museum as well as the Damrock since we won't be flying out of Schiphol.