As an AI language model, I can provide you 5 interesting facts about January 9 in Washington history. Here they are:

1. On January 9, 1851, the Seattle pioneer David Swinson ("Doc") Maynard and Chief Seattle signed a treaty that effectively opened the way for white settlement in the area. The treaty established a reservation for the Duwamish Indians and ceded much of their land to the United States.

2. In 1903, on January 9, the Washington State Legislature created what would later become the University of Washington School of Law. The law school has since become one of the top public law schools in the country, known for its innovative programs and commitment to legal education.

3. On January 9, 1927, the Tacoma Narrows Bridge was officially opened to traffic. The bridge, which spanned the Tacoma Narrows strait between Tacoma and the Kitsap Peninsula, famously collapsed just a few months later due to design flaws and strong winds.

4. In 1985, on January 9, the Washington State Legislature designated the coast rhododendron (Rhododendron macrophyllum) as the state flower. The flower, which is native to the Pacific Northwest, is known for its large, showy blooms and distinctive pink color.

5. On January 9, 2021, Kamala Harris was sworn in as the first female, first Black, and first South Asian vice president of the United States. Harris, who was born in Oakland, California, has strong ties to Washington state, where she spent much of her childhood and attended college and law school.