Volume of tractor = length x width x height = 301.5 x 96.99 x 105.04 = 3,071,630.624
For baseballs of 9 inches:

Volume =

Number of 9 inches baseballs =

For baseballs of 9.25 inches:

Volume =

Number of 9.25 inches baseballs =

Therefore, the tractor can contain between 229,824 and 249,513 baseballs.