List credit on your student’s high school transcript for non-traditional classes. It may not be a “recognized” curriculum title, but if it is a learned skill that they have developed, it proves they have the ability to teach themselves.
For example, if the student has devoted considerable time to an independent project (stamp-collecting, designing/making beaded bracelets, training horses, digital photo-editing, etc), think up a course title and write an appropriate description for it, listing any reference books as “texts used.” Include out-of-classroom work as well, such as seminars attended, etc. The “course descriptions” page of their transcript will provide the complete explanation. (If you are interested in how to write a transcript, see Transcript Writing.)
Listening to CSN radio (or to your pastor’s Sunday teaching) counts as Bible class; just because you have always listened to it, and would listen to it anyway, does not mean it should be overlooked as a “credit” course. The same applies to AWANAs, Sunday School, Royal Rangers, or similar structured classes your students attend.