Has an NPB (Japan) game ever ended 11-9?
Yes. NPB (Japan) has seen a final score of 11-9 44 times. It first happened on June 8, 1950, when Yomiuri Giants beat Shochiku Robins, and most recently on May 11, 2024, when Yokohama DeNA Baystars beat Hanshin Tigers.
That makes 11-9 the 94th most common final score out of 223 that have ever occurred in NPB (Japan). One point away, 12-9 has happened 35 times and 11-10 has happened 52 times.