I went to the Canon site by searching for Canon and getting there through their Worldwide www.canon.com clicking on the Thailand (English) button and reaching http://www.canon.co.th/home?languageCode=EN next click on the Supports and Downloads button and you are where you want to be.
Incidentally, the 8600F is also disabled through ElCapitan. I've enquired of Silverfast and they do not know when or if any support will be offered to 8600F users and I assume that applies to the 8800F.
Canon still support the 9000F and later but for how long? Who can tell?
I find it disgraceful that Canon think it good customer relations to abandon support for equipment that is 5 years old or even less.
Epson I see still support scanners over 10 years old, I just found a driver for their Perfection 1250 PHOTO Flatbed Scanner for ElCapitan, on Epson's site. There is a review of it on the eopinions.com web site dating from 2002.
I will be voting with my wallet when I replace.
VueScan has put out a version of its software which works for the 8600F and, I assume the 8800F so all is not lost but I do prefer the SIlverFast suite by far.