Doesn't look ballistic

 Ballistic missiles do not bore in from a horizontal angle and these missiles were likely cruise missiles, wing lifted horizontal fliers. Iran should have distinguished between the two types, they failed that test.

Show us the video. It seems like a pathetic act of war, nonsensical. Iran has a few million in repairs, the thing still works.  American oil companies would say this is stupid, so would the CIA, I think. The number of suspects is huge, Iran has all sorts of small enemies. A likely possibility is that the Saudis hired it done by one of the Mohummerdude factions.

In the Persian Gulf, take along a few surveillance drones to fly ahead of you. A small fishing boat over the horizon is launching drones up high, reporting video back. Once your tanker spotted, they send the go signil and simple software flies the drone into the ship. 

The equilibrium is obvious, we have created, out of necessity, the fully automated Persian Gulf drone police concept.  Oil cannot flow unless all the bots come to some sort of agreement.