When I went to download 1.8.9 Forge I accidentally got 1.8.8 instead. When I delete it from my .minecraft/versions it still stays in my launcher and it will not let me remove it from my launcher.
Its not necessary to remove old Forge versions. Just make a new Profile and make sure to select the Forge version you need.
"We live on a placid island of ignorance in the midst of black seas of infinity, and it was not meant that we should voyage far."