I would suggest trying to get it closer to 8 or later in the day......you MIGHT be let in around 8:45 but I wouldn't bank on it, and worse, with the park opening at 9:00 a.m. you will be caught in the stampede of people running to Frozen ever After which is exactly where you're headed, I don't think it would be a pleasant experience for your Father - my father is 77 and I would be really worried about people bumping into him and him trying to "keep up" with the rest of us. On a trip we took in March, we had a 9:30 Akershus reservation so I have done this particular route before. Check in will also be confusing, because the line will be building for Frozen while people are finding their way to the Akershus line as well. I knew where to go and what to do, but people around us were getting flustered because the line to check in to the restaurant was right where the line for the ride was building. It was a bit chaotic, so I would definitely try and change your time if you are able to so that you can really enjoy the experience without having to be caught in the mad dash to Anna and Elsa!