Di622 is not designed for Canon Proshot G9. We are sorry but it does not work on this camera. Nissin's instruction manual and brochure do not list this camera in the compatible camera list.
We feel it sorry, but will strictly educate our sales representatives to correctly explain about our product to the honest user.
For your information we have a smaller model, Di28 which is designed for small compact cameras, like Canon G7 and G9.