I have been reading the various responses about the castle. We are wanting to tour the castle on Friday , September 27. We will be traveling from Dufftown and will not arrive until after 12. I am checking for confirmation that prebooking is not necessary for this date. Most posts make me think it is not needed, but I just read one that was contrary. I am hoping that Sept. 27 is not a busy day, but it is a Friday, so possibly prebooking would be a good idea.
We were there last July and it was crowded. We bought tickets the day we arrived for the next morning. It doesn’t open until 9:30 am which isn’t early enough to beat the tour buses.
I had colleagues who went at 3 pm instead and it was far less crowded in comparing notes than first thing. They did not buy tickets ahead of time.
Now July is prime season so you might not hit crowds like we did anyway. But consider later in the day as an option.
September is really different from July. I have visited the first week in September and had virtually no line. In late in June we had a line on the weekend. I think you will be fine. It's wonderful place to visit. There are lots of things to see.
We were there last week. You can book online and save a couple of pounds as little as 2 hours ahead. We went the day before and bought tickets for the next day. The benefit of prepaying/prebooking is you avoid some of the lineups but those lineups weren't that bad last week. If you don't mind a bit of waiting to get your ticket then just go when you want.