First of all, see if there is ICE (Image Capture Extension) software for your scanner. This is usually found in /Library/Image Capture/Devices/. This is what provides device-specific support in Image Capture.

Canon does provide reasonably up-to-date software for the scanner. If it doesn't work, you should contact them for support.

I can select "Billions" in Image Capture for my scanner here:

Doing this creates a PNG file, which Affinity Photo reports as RGB/16, e.g. 16 bits per channel. (48-bit).

Of course, 48-bit is far and away more accuracy than the source material will yield, or that your eyes can see.