Can't see a William Adair age 21 in 1909 Londonderry to N.Y.
There is William Adair arr. NY 6 JUne 1909 but born Belfast.
1920 U.S. Census found in Chicago, Cook, Illinois a Wm. Adair age 36, born Ireland, to US 1906 chauffeur with wife Ida 29 born Illinois and daughter Florence age 9 months born Illinois. But this William is possibly son of William + Jane Adair (1910- Biggsville, Henderson, Ill.).