Welcome to the site!
I am sure the pics don't tell the full story, but rust is the cancer of these cars. The pics appear to show that rust is already present and starting to spread. This is a T-Top car and there is rust at the bottom of the doors. For every spot of rust you do see there are a bunch you don't. (search this board for ttop and rust and you will see what I mean) The under-body could be even scarier. When considering a project car, you need to be honest with yourself about what your strengths and weaknesses are in terms what you can do to the car, then compare it to what your goals are.
Every car has a story, but very rarely does the story about a GN project car have a happy ending unless you are already very skilled and already have plenty of surplus parts for these cars. Beyond the body work that would surely need to be done, there is the starting issue you know going into it. Additionally, once you get it started, there is the issue of getting it 'running' right so that when you jam on the gas pedal, the car behaves like you want it to. And then there is the interior.
As SpoolFool mentioned above, you want to buy the cleanest car you can possible afford. I know you are hoping to find a diamond in the rough, but it is extremely hard to do with these cars. Many people blow them up trying to get them to go faster, and then cant afford to fix them so they sit in decay.
If you were willing to spend 9k on this, I am willing to bet it needs at least another 3k in parts to get running. (Starter, brake system, all new rubber under the hood, gas tank/fuel system, plugs, wires, tires, cooling system) So you are at 12k , not counting your time and you haven't improved the paint/rust situation or the interior. Look in the for sale section of this board and see what 12k will buy you.
Again, if you are a body guy, and have access to parts, and a slush fund filled with cash, it is always good to see a GN get brought back to life. But if you are hoping this is just a $500 repair and a detail job away from your dream car, I worry you will be disappointed.
Just my opinion of course.
Good luck in whatever you decide!