18,000 is the official number from New Japan, so a little over half-full - Meltzer says the NJPW office were always expecting somewhere in the region of 16-18k, so they hit their target for the venue, even if it wasn't a sell-out. Incidentally, Japan's being hit by a typhoon at the moment, which may have affected walk-in ticket sales on the day.
New Japan also announced that the next PPV on September 21st, Destruction in Kobe, will be streamed via Ustream - no word on the September 23rd Destruction in Okayama event, though.