Students in schools that offer the Nova Scotia Department of Education High School Diploma are eligible to earn High School credits through two other channels:
All information can be found at the Personal Development Credits page of the Nova Scotia Department of Education website. And here is the PDC Information for Students and ParentsGuardians 2018-2019.
In a nutshell, some programs in certain organizations in Nova Scotia have already been pre-approved for high school credit. For example, if you are a Pre-Professional Dancer through Dance Nova Scotia, you may be eligible for Dance NS Ballet 12. Consult this document to see if you provider and course are eligible: Approved Provider and Course List for 2018-2019.
The procedure to challenge for high school credit can be found in this Guideline. According to the NS Dept of Ed, "The Department of Education and Early Childhood Development recognizes that students may have already acquired the knowledge, skills, and attitudes that an existing course seeks to develop. Challenge for credit provides a process for students to demonstrate that they have achieved learning outcomes as defined in the Public School Programs and the curriculum guide for a directly-related course."
(Here is the current Public School Program document - 23 MB which is the accreditation guide for all Nova Scotia public schools, and private schools with the permission to grant the Nova Scotia High School Diploma / Leaving Certificate).