the 7.6, 8.3, 8.7, 9.6, 10.7
These were a family of boats developed by Australian designer Alan Payne in the mid 70's. We owned an 8.7 for 15 years. These are East Coast boats by the way. Built in Chesapeake Virginia before Columbia sold the molds to Hughes and Hughes then sold them to Aura.
The 9.6 is an outlier. The other boats were sold as "wide-body super cruisiers" and as such were one of the first series of production boats where a boat builder went to a designer and asked for something new (as oppsoed to a designer trying to shop his designs). The 9.6 on the other hand has a lot of hull form commonality with Payne's Austrailian 12 meter Gretel.
As such it is a more lively hull with less wetted area than the others (on a relative basis). However it is more quickly affected by loading for cruising as a result. While it had less room below than the super cruisers, it was comparable with other boats its length at the time. It is decidedly cozy compared to equivalent length boats today.
Columbia attempted to build all the x.x boats on a production line basis. I visited the plant before buying ours (in 1977) and their approach had much in common with concepts being used today in Europe. However, the technology and skills base at the time was not quite ready.
The good news is the early boats were essentially blister free boats. Builders hadn't started cutting corners yet. The bad news is below the ok exterior finish there was some pretty sloppy work on the interiors and window areas. I did a lot of fixin'. Ours had a cored deck and we were getting some softness in the foredeck at 15 years.
Columbia had a few problems with suppliers. We had to have keel nuts replaced and the masthead tangs were recalled. Kinda significant things in the first year.
Ours had a Volvo MD-6B. A very, very reliable engine that would run forever but couldn't push the boat into a chop. The two blade prop hid behind the keel but it had limited thrust.
We sailed Freelance on the Gulf Coast, we sailed her across the Gulf and up the ICW to the Chesapeake. We sailed her off Los Angeles. We sold her in 1992 for $18+K
We loved the boat and trusted it. It was fast, weatherly, simple and just enough overbuilt that problems could be dealt with before the became serious. It had just a tiny wiggle when the wind was at about 170 degrees relative.
All that said. If you are looking at a Columbia 9.6 from the mid 70s, I wouldn't pay more than $10K for one.