Jay gives the details in his excellent book.
Sometimes you get a table that is 'friendly' to sending the 9 towards the corners. I think Joe Tucker said this happens when the rack settles with a tiny gap behind either of the balls behind the 9... and then you have to break from the side.
I don't think earl did any rack mechanics to make himself a dead 9. He just got fortunate that this table was doing that. So yeah, he got lots of early 9's and 9 on the break.
The insurance company stipulated that after 5 racks, a neutral racker had to be found. Jay, catching on a little late, stepped in after 6. Then jay racked them himself. But still the table broke friendly, and earl was just running out as needed.
He hit the 10, and then, just to be safe, he actually pulled off an 11th break and run (in case the insurance company got squirrelly about the racking issue).
They still didn't want to pay due to the 9's on the break / early 9's. But it wasn't spelled out in the original contract. So while earl didn't win the whole million, he made a settlement with them for something like... I think it was less than half of that? Can't recall. A significant fraction of it.
Efren has run a 9 pack in competition. In fact I think maybe more than one. That one's on youtube. Only Jay H. and maybe a handful of others have the video of Earl's run.