TOKYO, Feb 10 (Reuters) - Japan's Toyota Motor Corp , the world's biggest automaker by vehicle sales, on Wednesday posted a nine-month operating profit of 1.51 trillion yen ($14.44 billion), down 26 from 2.06 trillion yen a year ago. ($1 = 104.5500 yen) (Reporting by Eimi Yamamitsu; Editing by Kenneth Maxwell)