The search function is your friend. There is a thread on maintenance items for 9000 series walker machines. It is pretty complete.
If they havn't been replaced yet, I think you will need a new feederhouse chain and sprockets, new concave and cylinder bars, and maybe a new vertical unloading auger. Probably also needs new walker bearings. Replacing the factory aluminum POS with wood seems to be the thing to do.
Whether its a good deal or not depends on the price. Your opinion will depend on what you are replacing.