The nvidia driver before 9755 was for less than 6000nvidia models , 9755 or later as for 6000 or above cards.
On nvidia website there is the search function I just found my fav. version nvidia 9755 using this.
It should end up listing in the search results the nvidia 96?? .run file.
Then logout of X using console login at login window and run the file as root with " sh ./NVI*.run " provided you are in the same folder as the downloaded driver.
You should also be able to emerge the 96?? nvidia driver's somehow I have no clue to exact way. google.com and search for "gentoo nvidia 9639"
IA32 = intel 32 bit the 96 ?? is the one you want. Next page right click and save to desktop then install. Might complain if /usr/src/linux is empty so check if you have a kernel downloaded close to the same one you are using now.
should fix this then isntall.
Hope this helps.