As I mentioned in my previous comment, till the time you don't prove you are a full-time student, you do not fulfil the requirements of Spouse Open Work Permit. You need to have a current enrolment letter issue from your college specifying you are a full-time student. I don't know why you deferred but could have started with online classes if your college offered. Due to COVID reasons, this is acceptable.
On your query about 6 months, there is no explicit mention of any 6 months rule anywhere but there is an underlying principle of requirements for Spousal Open Work Permit. It is never advisable to apply for SOWP with a study permit less than 6 months. Reason 1: The study permit is normally issued for the date of completion of the program plus 90 days. Once, you receive a letter of completion from your educational institution you cease to be a full-time student. Reason2: In last semester, students can also go for part-time studies. This again is in contradiction to requirement of SOWP of being a full-time student. So, generally, a refusal reason based on the 'duration of the length of visit' is given by a visa officer.
So, you have 2 options 1. either extend your study permit as you already have to do due to deferment or wait for PGWP and apply under C41 with NOC 0, A ,B job offer and 3 pay stubs.
Note: If you come from Northern India then due to too much abuse of SOWP especially in Punjab, you can expect an extra layer of scrutiny to your application.