I'd say that's probably very doable, but agree with mom2rtk - be close to the train station, or at least midway on Main Street. If you get caught by the castle, getting out could take 15-20 minutes. But once you make the park exit, it's a simple walk to SH71. I think the fireworks were around 20 minutes, so you'll still have a goo 30-35 minutes after to get to your ADR. And it's probably not an issue if you get there at 9:00. Keep in mind (not clear when you are planning to do this), but if you do it this month on the night of a Christmas party, Main Street is almost impassable around the 8:00 fireworks - day guests heading out and party guests arriving.