Yes. As long as there is still availability for the 9 am slot, you can have it. Book it at 60 days and you shouldn't have any problem at all.
Just a reminder that doing that will mean you can't FP rock n roller coaster.
If RnRC is on your list, I would recommend TSMM at opening, then RnRC stand by or single rider and then a FP for TSMM later in the morning. That way you're still riding twice, but not using your FP during the easiest stand by time of the day.