Canon are pretty useless when it comes to providing scanner drivers for older hardware on newer releases of OS X. I have been caught out twice, and no longer buy Canon. I now use Epson flatbed scanners.
You might give
VueScan a try, it is a 3rd Party solution that works with a large number of scanners, but it is not cheap. They do have a trial so you can check in works first before buying. To be honest I would just get a new scanner, you can pick one up pretty cheaply these days that is not a lot more then a copy of VueScan.