* 9 liters? There are 1000 ml in 1 liter, so 9 liters would be 9 * 1000 = 9000 ml

* 9 cubic centimeters? There is 1 ml in 1 cubic centimeter, so 9 cubic centimeters would be 9 ml

* 9 gallons? There are 3785.41 ml in 1 gallon, so 9 gallons would be 9 * 3785.41 = 34068.69 ml

Please specify what unit you're referring to so I can give you the correct conversion.