What is the pressure in a 9 Gram CO2 canister such as those manufactured for low end guns and similar to ones that contain nitrous oxide whip cream?

The pressure inside a 9 Gram CO2 canister varies depending on the temperature, but is typically between 590 and 850 psi (pounds per square inch). This is approximately equivalent to 406 and 586 bar (bars), or 4.06 to 5.86 megapascals (MPa).