Not a good idea. Most those guns are designed to mix soda syrups and carbonated water. Some handle pre-mix and might work with beer. Find out the part numbers, because oddly enough I can't find any 9 button guns on their site.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk