There's a web site called ibdozing.com that has a bunch of TD9 restorations and lots of great pictures of various peoples TD9 of various vintages. Perhaps there would be the spot to find out more. For some reason my browser won't let me look at the new message board, but the projects setion is fun.
A quick search through that forum finds a guy who claims to have a book that shows the TD9 at 10,240 lbs. Of course this is third person and just because it's in a book doesn't make it right. What's more, you never know but that it's the same person who said a similar thing on other forums.