I went to IoA on the 14th and only had to wait about 10 minutes for HPatFJ. I got to ride it 3 times.
I also only had to wait in the line for Ollivanders for 10 minutes. Got butterbeer in 5.
Had to wait in zero line for the merchandise.
I AM SO GLAD I WENT THAT DAY.
9 hour lines? Holy crap. I have to say though. The ride was incredible and that section of the park is incredible. I guarantee you they will be expanding the Wizarding World by a couple of lands in no time. They are going to be making billions off of the merchandise. I know I got a wand, and a bunch of other stuff.
I love HP, and I don't really care that its not Disney. I love disney World and always will, but, I can't deny that WWoHP is oozing of quality. Its just fantastic and feels like you're in the harry potter universe. I loved all of it.
I just got back from my trip to WDW and I have to say that my trip to Islands of Adventure was one of my favorite moments on this trip. I will definitely be going again. (and this is coming from a guy who thinks Universal is mostly useless).