A typical CFI course takes 6 weeks or less to complete full time. One can't just "drag it out" to 8 months for visa purposes.
Immigration & Citizenship Canada wont even issue the required Student Visa (> 8 months) unless the flight school provides an official letter of acceptance stating a course length longer than that, and the student provides banking info guaranteeing the funds for tuition / flight hours plus living expenses for the stated course length.