Hmm, that will be close/tricky, especially on a busy day like today. I think it will come down to how backed up the RSR FP return line is (inside) - we often wait 10-15 minutes or so to get on the ride after that first scan point.
If you want to try it, I'd be there at RSR ready to scan in at 8:15 (if there's a FP return line, get in it a couple minutes early), and then when you get out head out of the main entrance to Carsland and look for any space that's available. If you head up towards the Pier, you'll usually see some open spots that you can stand in.
You could also wait for the parade right by the Carsland entrance and wait for the parade to end, then use the end time on your FP. Keep in mind that an end time of 9:20 means you can actually scan in anytime before 9:35 (disclaimer: I'm always too chicken to count on that last 5 minutes, but I routinely scan in about 10 minutes "late").