Hi,
Yes, the canonical URL system will allow you to have always the same URL going to the product page. If that's not the case, and that you have set the "Force canonical URLs on listings" option of the configuration correctly and that your products have a canonical URL, then the only thing left are the views modifications.
Rename the folder templates/YOUR_TEMPLATE/html/com_hikashop and that will deactivate all the overrides. Then, you'll see if your module is displaying the canonical URLs or not and you can rename back the folder.
That way, you'll know if it comes from the view modifications.