I noticed the Cressida isn't listed as a model that's excluded from retrofitting with tether anchors on the listing of excluded models on the first page of the LATCH manual Toyota's section (noticed this while looking up Land Cruiser info. for another thread). That absence from the excluded Toyota model list very likely means a Cressida would be retrofittable using the Toyota tether anchor retrofit part number 73709-12010 used for all retrofittable Toyota models. Hopefully the Toyota dealership can confirm, and laying hands on the Cressida owner's manual can possibly clarify the specific locations for retrofitting tether anchors in the car.
While Toyota doesn't have an official free tether anchor retrofit program, in the U.S., SafetyBelt Safe USA (who has the other carseat.org site, the one without the hyphen
) partnered with Toyota to offer a reduced cost voucher program for retrofittable Toyota and Lexus model owners for a donation of $5 per tether anchor, but unfortunately that reduced cost program isn't available for Canadian owners
(assuming the OP is asking about a Canadian car). Best to get a price quote from the Toyota dealership to avoid any surprises on tether anchor retrofit pricing.