I'm currently programming a Spigot plugin by using several worlds with Nether and End. So you should be able to create a new world with a command, then teleport to it and be able to play there. You should also get into the Nether and you should be able to kill the Ender dragon (play through Minecraft). But you should also be able to delete this world with a Coammand. I have already tried to create Nether and End Worlds that are called [weltneme] _nether or [weltname] _the_end, but it didn't work either. I really can't find a solution for this on the Internet.
There's already a known plugin called Multiverse 2, which can do all of the above (https://www.spigotmc.org/resources/multiverse-core.390)
They have their code on GitHub (https://github.com/Multiverse/Multiverse-Core)
That should help you.
