It shouldn't be a problem to follow him later. If they give you a visa, it will have an expiry date on it and you must travel to Canada before that date. Make sure you are able to prove you meet the criteria of a common-law spouse (living together for at least 1 year). Yes, if he wants you to go with him or follow him later, he MUST include your name on the form.
Rjessome,
Thank you so much for your answer, by the way what is open working permit ? does it mean i can work and then resign in any company without informing immigration ? and can my bf and i get married in Canada while his is studying there ?