The C9 was just according to the sheet music I have for Immigrant song.
Now if Jimmy stated that it was an unusual G chord the C9 aka "3233" wouldn't make sense because there's no G note in that chord (the notes being C, E, B-flat, and D), whereas the notes in the so called "3533 chord" that was proposed earlier would make sense (The notes in that chord are C, G, B-flat, and D). I'm not sure what you would call this chord, but it is some form of G considering that all three notes of the G-Minor Triad are present (G, B-flat, and D).