When Martina Navritilova won her ninth Wimbledon Singles title in 1990, whose record of eight wins did she beat?

Answer: Helen Wills Moody (USA) 

Helen Wills Moody (1905-1998) was an American tennis player who won a total of 31 Grand Slam titles from 1922-1938. This total included 19 singles titles (8 x Wimbledon, 7 x USA and 4 x French). On top of this she won two gold medals (singles and doubles) at the 1924 Paris Olympic Games. 

Billie Jean King (USA) played from 1968-1983; she won 39 Grand Slam titles including 12 singles (6 x Wimbledon, 4 x US and one each in Australia and France). Margaret Court (Australia) played from 1960-1977; she won 64 Grand Slam titles including 24 singles titles (11 x Australian Open, 3 x Wimbledon and 5 each in the USA and French Opens). Suzanne Lenglen (1899-1938) was a French tennis player who won 21 Grand Slam titles from 1914-1926. She won the Wimbledon Singles Championship 6 times.
Source:  Fun Trivia.com and Wikipedia