How do I get the formula to either add 1 or stay the same?

I have one cell that already has and adding formula. Now I want to say, if that answer is between 0&9, add 1. If the answer gets to 10, stop adding and leave it at 10. Basically, my employees accrue one PTO day per month, not to exceed 10 in a year. So I have, cell E11, E9+1. Now in the same cell, I was trying to tell it that when it adds that +1, if the answer comes out to be 0-10, that’s cool. But when the answer comes out to be more than 10, to just keep it at 10. I want the cell to stop adding +1 when the value gets to 10.