I think that rift between Mick Jagger and Keith Richards in the 1980s counted as one of the world wars. I am not sure about the remaining eight.Good point.
Let’s see, there’s the war on poverty, the war on obesity, the war on drugs, the War of the Worlds, (does that one count as two?) the war on the truth, the war on unsightly stains, and I guess you could count that whole Yoko dust up.