Can I travel back to Canada, the moment I receive portal email? and reply to email once I reach Canada!
Yes. The portal email asks you to confirm details as soon as possible. Some emails ask them to do it within 7 days.
The last 3 questions of the email are
Are you currently inside Canada? (Yes/No):
If you are not inside Canada, when is your expected return date?:
If you are not inside Canada, please specify your current location (city and country):
You can always reply to the email at least to acknowledge it. If you do reply to this, they should send you a follow up a few days after the expected return date.
You won't get a eCOPR until after you get PR Portal Credentials and confirm everything.