Depending on the cut of the chamber, 9x19 may not fit as it's too fat just in front of the extractor groove than the .38 super is at that dimention.
On top of the other issues raised here, gas cutting is a very real possibility. As the chamber is about 4mm longer, and the 9x19 case mouth is likely smaller than the .385 straight cut .38 super chamber, gas leakage is a possibility.