You bloodthirsty, banana-crazed maniacs! Jotaro doesn't kill anyone who A) Isn't named DIO, B) Doesn't mess up his hat or C) Doesn't attempts to kill his daughter Jolyne.
Since Jolyne isn't born yet, then Jotaro will only kill DIO and anyone who destroys his hat. other than that, he doesn't kill. Plus, we don't have 5 seconds time stop yet, so we can't use Road Rolla Da, which takes 7 seconds to even bring the road roller and 8 seconds to fully complete. Therefore, Jotaro can only use pistols, spears and knives to overkill a target in case he doesn't get knife PTSD. And that includes long rage timestop. He can also probably slice people in half like Diavolo and [King Crimson] or doughnut a person with ease, since he performed an "ORA Doughnut Barrage" on DIO, as well as remove the entire upper half of his head with barely any effort.
However, all of this is for a bloodlusted Jotaro, which never happens since he doesn't believe in killing an opponent.