It may come as a surprise but the Canon G9 is not waterproof, in fact if you look down from the top and look at the diopter adjustment wheel you can see into the camera (easier to see when the camera is on)
Now the easy way to deal with this is to use a the Canon waterproof case WP-DC21, but its some what over the top for occasional bad weather.
Last year on a protest march from the Climate Camp to BAA’s offices, it was raining, and raining a pretty young journalist took pity on me and gave me her umbrella and I suddenly realised the potential in keeping camera and lenses dry when it’s raining. Not all my problems were solved though, as I was using a Nikon D2x DSLR it requires two handed use so as to date I have not invested in an umbrella as yet.
However the G9 is usable one handed; you can zoom, focus and alter nearly all the options one handed, with perhaps the exception of the print/shortcut button and ISO dial (both can be accessed by tilting the camera and using a finger that holds the umbrella) so its time to go and by an umbrella.
One type of umbrella I don’t recommend is the big golfing ones, they are very unsteady in the heavy wind which will be hard to handle the G9 or throw you off composing your picture. My recommendation is the small collapsible ones that will fit easily into a spare space in your Laptop bag, messenger bag, camera bag or any other bag you carry
It is also a good idea to keep a polythene bag with you to store the G9 in, keeping it dry if your bag gets drenched!