Having the same issue. Crashes on launch. Will attempt deleting and reinstalling. I won't update my iPad. Update: yup. That worked. *sigh.
I was able to do this: click on your Library of Notebooks so you see the images of the notebooks in the single window. Hold the control key down and click on any notebook cover that you want to delete: a menu list will come down with the option to delete a notebook as the fifth option. (I don't have a mouse so right-clicking is out of the question.)