The printer driver for the i9900 is available from Apple Software Update, as per this KB article.
If you connect the i9900 to the Mac, the printer should be recognised by the OS and the supporting driver downloaded from Apple.
Regarding the CP760, Canon has not released a supporting driver for Mtn Lion yet. Some users have managed to get the driver for Lion to install on Mtn Lion, but it does require a fair bit of effort to achieve success.
I tried downloading the software again tonight and received the following message:
Can't install the software for the Canon i9900 because it is not currently available from the Software Update server.
I also manually downloaded the Canon Drivers from the Download page from Apple and installed it, however, I still not having any luck getting this Mac Book Pro to recognize the printer. What's even more bizarre is on my 2008 MacBook Pro that has been updated to Mountain Lion this printer is recognized.