Must I use provincial curriculum?

No province in Canada mandates that homeschoolers use exclusively provincial curriculum. 

Some provinces with more than one option for schooling at home have an option which includes use of provincial curriculum, and others require homeschoolers to use curriculum from an “approved” list or to get curriculum approved if it is not on the list. For more information, see the Summary of Provincial Laws across Canada. 

However, in most provinces, homeschoolers are free to choose from an ever-growing array of homeschool curriculum and resources.

This list of Homeschool Resources may be very helpful.