“The Pirate catcher [Earl Smith] is one of the league’s ‘pull’ hitters; that is, Earl, a lefthand batter of the slugging type, smashes most of his wallops to rightfield.” Chilly Doyle, Pittsburgh Post-Gazette, January 26, 1925, p9
Previous earliest use (Dickson Baseball Dictionary, 3rd edition, 2009):
1ST USE. 1928. “Most batters who have trouble with slow ball pitching are ‘pull’ hitters. That is, they are meeting the ball ‘out front’” (George Herman Ruth, Babe Ruth’s Own Book of Baseball, 1928, p. 164; Peter Morris).