Dumbledore Revelations

So Rowling has "revealed" that Dumbledore is gay. This brings up an interesting issue of what is "true" about book characters and plot if it's not in the book. I mean, sure, I understand that maybe this is how she has thought of him all this time when she was writing, but if you don't put it in the book, do you get to post facto make this part of the story by stating it at a reading? Are we to incorporate everything an author says or writes about a character into our understanding, even if it's not in the book(s)? I haven't totally fleshed this out in my mind yet, but I sort of think that if you want to make this part of the plot and/or character, it needs to be in the book. Otherwise, you are just leaving it up to reader interpretation, and while you may have your personal authorial take, it's not actual "fact." It kind of reminds me of Stephenie Meyer saying how she worries about "solidifying" plot and character elements on her website. In a way, I like the idea of authors clarifying their thoughts about characters and explaining things and having "extra" information on their websites to supplement stories, but on the other hand, I tend to think this as much less "official" if it's not in the book. Is everything not in the book up for grabs (a la fan fiction)? I'm torn right now.