A 9-year-old takes about 10.75" at second base or shortstop (10.5–11.25"), 11" at third and 11.75" in the outfield. At 9 a player can be in Majors (46 ft pitching, 60 ft bases). Typical hand: 6.25–6.75"; median height 4'6".
Two charts at 9
Rawlings lists youth 7–12, infield at 10.25–11.5"; Baseball Monkey’s baseball, ages 8–10 band gives 10.5–11.25". They overlap at 10.5–11.25", and the sizer picks the middle: 10.75".
At 9 a pitcher’s glove (11") wants a closed or basket web, a middle infield (2b / ss) glove of 10.75" an I-Web, and a third baseman’s 11" an H-web.
The game at 9
In Little League a 9-year-old plays in Minor League (ages 5–12, 46 ft pitching, 60 ft bases); Little League (Majors) (ages 9–12, 46 ft pitching, 60 ft bases). Pitchers are limited to 75 pitches a day at this league age. The next step is Intermediate 50/70 from 11.
CDC growth charts put the median 9½-year-old boy at 136.3 cm (4'6") and girl at 135.6 cm (4'5"); the 5th to 95th percentile for boys runs 4'2" to 4'10". A tall player at the age is often a size ahead in the hand too.
Check the hand
Rawlings’ batting-glove chart puts hands at 9 in Youth Medium (6.25–6.5") and Youth Large (6.5–6.75"), measured from the base of the palm to the tip of the middle finger. Measure it 1:1 in Mode 01 (finger plus palm): a longer hand moves the pick toward 11.25", a shorter one toward 10.5".
For comparison, the 8-year-old sheet starts from 10.75".