Yes, in certain cases a parent can be held liable for their children's torts. Indeed the particular states laws plus WHAT THE CONTRACT ACTUALLY SAYS determines if indeed the parents homeowners covers their kid torching another house/barn. From experience with insurance companies, I just don't envision them rushing in there eager (drag them in kicking and screaming lol) to pay for what that those kids did...... BUT THE POLICY RULES no ones opinion as to what's fair or "should be" covered. As far as personal liability coverage in a typical homeowners policy, I view that more about you're liable if someone is injured on your property (or even if you drive and injure someone) and you're found negligent VERSUS you're liable if your kids go elsewhere and torch a barn. BUT AGAIN ITS NOT WHAT I OR YOU THINK ITS WHAT THE POLICY AND STATE LAW SAYS. I nor anyone cant say NOT having read the homeowners policy, but a homeowners policy that pays for damages if your child torches someone else barn Id have to read and research it prior to rendering a more professional legal opinion... As you well noted INTENTIONAL might be most relevant !!!
As always, fun chatting
John T Country Lawyer