FWIW, B&S 9 collets are plentiful and very reasonably priced these days. I just bought a full set, new, ground and hardened for $145.00 . little machine shop carris them, as well as several eBay vendors. I wouldn’t worry about B&S availability for this machine.
Regarding whether to buy or pass, I’ve kind of reached the point that if it where me, I would pass. And keep Looking for a decent used machine for not much more - $2500 or less.
In your photos, the machine scrapings show a lot of what looks like localized high production wear in one or two spots. This is usually caused when the shop doesn’t move the set up and fixtures back and forth on the bed to equalize wear. This is very poor technique, suggesting poor maintenance and early,often fatal wear and tear. It’s likely the never been used throughout the full travel of the bed - meaning you might be fighting abnormal bed wear in the usual middle position- forever causing you set up problems.
Also the broken parts and loose travel etc mean you will have to spend considerable time chasing parts or fabricating something from scratch. Overall the machine seems to have had a hard life. I have a theory that indifidual parts don’t wear out on machine tools - rather, all parts wear at the same rate. Some just break earlier than others. Basically the machine wears out everywhere, over time. So several worn, broken, or missing parts, means all the rest of the machine has experienced the significant wear and tear. Something to beware of...
It’s fun to contemplate buying old machines. But I’ve found its more fun to buy one that works, and just go make stuff!
Glenn