If I'm absent one day, can I just stay late the next day?

No, you can not make that decision without first conferring with your Co-op teacher and especially your placement supervisor. The Work Education Agreement provides WSIB coverage only for the times spelled out in that document. If you stay late, outside of those hours, you will not be covered by insurance, should not be there and will not be able to count these hours.If changes to the schedule need to be made, or hours need to be made up, talk with your Co-op teacher to make the arrangements properly.