I haven't seen one yet and if it does exists, its rare to see one.
No, it's not possible. You can only do things inside of ROBLOX, closing their application is impossible. You could kick the player from the game, that is a way to remove them from the game, but not closing the application.
In Roblox platform convention TofuBytes is true. But as long roblox player i know there is AN NOT CONVENTIONAL way to make this button. OK. What it mean? You can make roblox player broke by several ways using calculations. Making a lua loop that 'endlessly' will loop and calculate something is generally way to crash it. But still that make only show a information that roblox player doesn't respond(it cannot finalize its scripts). (I think there is also other way but only roblox corp. devs know it)
That all i can help as low level lua developer and high level roblox player :D
No, there isnt a button to remove a Players Account