I'm not entirely certain on if they'd fit a jean size 9, they may be too big for you but I'm not sure. The way they factor the sizing is with height and weight. If you click on the third photo and enlarge it (not the second photo of the actual box, but the photo after it), it should make it easier to see. Hopefully anyway :).
Else they do have the size chart on their site by going here: http://www.nononsense.com/sizecharts/images/NN-KH-One.jpg