http://iscoresports.com/

Using iScore v. 4.51(?)--latest version
iPhone 5
iOS 8.1.2

I accidentally had a 10th batter in my batting order when I started the game (at the bottom of the roster list).

Around the 4th inning, I realized my error and tried to correct it by pressing Starting Lineup in "Misc." It removed the player's name off the batting order, but a "Null" batter still came up to bat.

You have to remove the batter prior to them coming up to bat. If you realize after the player is already at the plate, use an Undo, remove the player from the lineup, then re-enter the last pitch for the 9th batter. It will then bring the first batter up to the plate.