Can a president get rid of players who have not played for a while?

Yes, tap on the club's icon to pull up the club roster. Tap on the red button to the right of the member's name to remove them from the club.

Yes. As a president one can delete any player from their club. Click on your club name to see the list of current members. Each will have 2 buttons next to their name. One is red with a slash through it. Click that and it asks if you are sure you want to remove them and below it is a button that says “Remove” . Click it if you are sure you want that player removed from the club. It is my understanding that officers can also do this.

Can the President remove inactive players from your club? Of course.

The president or any officer can remove a player.

It's helpful to have a clear club policy specifying the minimum level of participation expected of members.