This problem is basically [tex]_{16}P_9[/tex]
[tex]_nP_r = \frac{n!}{(n - r)!}[/tex]
If I plug in n = 16 and r = 9
[tex]\frac{16!}{(16-9)!} = \frac{16!}{7!} = 4151347200[/tex]
So there are 4151347200 different nine player batting orders that can be chosen from a baseball team of 16 :)