Hi! While Videotron subscribers are currently unable to log into CTV's own streaming service, you should most definitely have access to their on-demand content on your Helix terminal. Press on the "Helix" button, go to "On-demand", navigate to the right to "Channels". You will then be able to select "CTV" and see their on-demand content. Else, you can also do a voice search for your favorite show and see if it's available on-demand.
This being said, you can also access on-demand content from lots of channels online through the helix.videotron.com website or through the Helix mobile app.