Sheesh, that's amazing. My HND-IAH in early October is still showing $4500 (1 pax) to jump from PP to Polaris even thought only 9 seats have sold so far. Woof.
I assume you mean NRT? 9 sold on a 789 is nearly 20% of the seats. That's probably above their trend line; most business class seats are sold within 3 weeks of travel. (Also, there's no way to tell how many seats have actually been sold, because not everyone picks a seat when they buy a ticket).