Size and weight is a big decision factor when you are trying to find the ideal camera for your needs.
In this section, We are going to illustrate Canon G9 X and Leica M-Monochrom side-by-side from the front, back and top in their relative dimensions. Canon G9 X has external dimensions of 98 x 58 x 31 mm (3.86 x 2.28 x 1.21″) and weighs 209 g (0.46 lb / 7.37 oz) (including batteries). Leica M-Monochrom has external dimensions of 139 x 80 x 37 mm (5.47 x 3.15 x 1.46″) and weighs 600 g (1.32 lb / 21.16 oz) (including batteries).
Below you can see the front view size comparison of Canon G9 X and Leica M-Monochrom. Canon G9 X is clearly the smaller of the two cameras. Its body is 41mm narrower, 22mm shorter and 6mm thinner than Leica M-Monochrom. As you can tell, actually this is not a fair size comparison since Canon G9 X has a built-in lens but Leica M-Monochrom doesn't. Once you put a lens on M-Monochrom, its thickness will increase significantly.
Here is the back view size comparison of Canon G9 X and Leica M-Monochrom.
Now lets look at the top view comparison of Canon G9 X and Leica M-Monochrom.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Canon G9 X is significantly lighter (391g ) than the Leica M-Monochrom which may become a big advantage especially on long walking trips.
Again, this comparison may not be very useful in real life as we are comparing the weight of a camera with a built-in lens to the body-only weight of an interchangeable lens camera. Once you put a lens on M-Monochrom, the total kit will weigh much higher.
Unfortunately neither Canon PowerShot G9 X nor Leica M-Monochrom provides any type of weather sealing in their body, so you have to give extra care especially when you are shooting outdoors. If weather sealing is a must-have feature for you, check these sections: Top Compact Cameras with Weather Sealing Top Mirrorless Cameras with Weather Sealing
LCD Screen Size and Features
Canon G9 X's 3" LCD screen is slightly larger than Leica M-Monochrom's 2.5" screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.