What can be done about books that are posted in the wrong genre?  I just clicked on a book in Baby to 3 that is actually rated 9 - 12 yrs.

You can edit the book data to show the correct information. Go to the book page, go to more options and then edit book data.

There is a box where you can fill in the reason for the edit and you can change the items that need to be corrected.

Someone from the book data correction team will be able to see the edits you submit and they will approve (or not, if there is a problem, but they will usually let you know why).

I don't bother correcting genres anymore.  I used to do it in a few genres in which I have quite a bit of expertise and experience, but I got tired of my corrections being disapproved by people who had no idea what they were doing regarding the genres in question.  Now I pay no attention at all to genres, because I know that, at least in those in which I'm most interested, a high percentage of books are miscategorized, so the genres are meaningless.