There is nothing near 9W with a 20% plus grade except for Old Mountain Road, but that is up near Nyack, and I'm not even sure that road gets that steep. If it's the road up to the Alpine police station on the northern end of River Road, it's 7-8% tops at the steepest points. If it's that short climb up to Englewood Cliffs, that road may have one or two 12%+ sections, but bicycles are really not permitted on that stretch of road.