“The killer whale’s teeth are designed to grasp and puncture rather than slice and tear like a shark. If the killer whale can’t swallow its prey whole, it probably can’t eat it unless it spins like a crocodile to tear off bite sized chunks.”
Killer whales commonly kill and eat other whales and do not swallow them whole. They also are known to eat sharks including great whites.
The article suggested the shark was swallowed whole, or transported intact very rapidly to great depth where it was eaten.
My understanding is that killer whales do not dive anywhere near the depth cited. Sperm whales do. Something the size of a sperm whale might be able to rapidly descend with its jaws locked onto a 9 foot shark which it would later swallow whole.
My guess is that the shark was diced and sliced at a shallower depth by one or more sharks. A chunk containing the tag was swallowed at which point the swallower headed for deeper, safer water to rest and digest the meal.
Whatever it was, it had to be big enough to swallow almost 10 feet of apex predator, and quick enough to drag it almost 2,000 feet in a few seconds.