It would blow a stock bulb. You could run it with 7 cells and 2 dumy AAs in that 9AA adapter. 8 cells would likely blow a stock 6 cell bulb on fresh cells but I can't be certain.
If you want to run on 9 cells, assuming that you're using NiMh cells, you can find a few good G4 base bulbs available. Then just plug the bulb into a 5mega or Kai socket and you've good to go. Just be sure you add in an aluminum reflector (with a hole big enough to fit your chosen bulb) and a borosilicate glass window.