Can I take credit for contributions to study materials on my CV?
These are not academic publications that you can legitimately claim on your CV.  At best, you might be able to describe this work experience in a different part of your CV, but keep your publication section clean.  A publication is one that you claim authorship of the given product, whether it is a peer-reviewed article, book, book chapter, monograph, etc.  Once you have a stock of publications, then you can create some logical categories.