Yeah, I'm gonna agree with most people here. Not enough details, but I most likely would not have taken the shot, unless they had done something violent in the store.
It would suck that they get to steal stuff, damage my car, and just drive off-and I get stuck with the burden of having to repair my vehicle... but still not justification to shoot. (let's be honest with ourselves, these guys aren't getting caught. Not for this, anyway.)
Although.... a few bullet holes in the trunk, or a shot out tire DOES make it easier for the cops to pick them out and catch them.... Not that that's a reason to justify a shooting but still, it's something to think about. should you be able to deploy a firearm as a tool for that purpose if you reasonably judged that you could do so without causing undue risk to human life?