When we get our fast passes for Racers and say the return time is 1:00--will these work later in the day too? I've heard the ride is really cool at night and want to wait until around 9pm to use them. Will the passes still work?
Yep, you can go anytime after the start of your window. They might give you a funny look or a snide comment, but they'll let you through.
Mission: Visit every Disney park in 365 days.
Tokyo Disneyland & DisneySea: 10/14
Disneyland Paris & Walt Disney Studios: 11/14
Disneyland California & California Adventure: 12/14
Hong Kong Disneyland: 3/15
Walt Disney World & AK & Epcot & DHS: planned 8/15
For a very busy ride like RSR, I would suggest coming back during your assigned hour. Like others have said, many people are going to use their Fastpass to ride it at night so you may end up having to wait a while to get on.