Has anybody been able to solve the question
how to use Canoscan 9900F scanner with Windows 7?
Yes, finally it occurred to me how to do it. It turns out to be very simple.
The only thing you need to have is a WinXP CD with registration code. If you have that (probably, since you upgraded) download the free VMware manager.
Once VWware is installed, install WinXP as the operating system of your virtual machine, upgrade to SP2 (if necessary), install drivers, switch on shared folders with your host computer, pass the USB connection with the scanner through to your new virtual XP (easy), and off you go scanning again.