FMJ .45 acp has killed people for the last 109 years, through both World Wars, and every conflict since it's still be used by SOCOM units.
This is the very reason I will always own a .45 ACP handgun in one form or another. I figure if stuff goes wrong and I should run out of .45 JHP I can use FMJ with little worry. I also always have a fair amount on hand. ( at least 200 rounds )
I wouldn't use 9MM FMJ unless there simply was no other choice.