I can't figure out how to install it on mac, and i'm pretty sure its an exe file.
I'm assuming you are talking about a server...
Although I cannot say this with certainty, I do not think you are allowed to use that spigot plugin. Spigot, Bukkit, and Paper are considered modded, and thus banned for speedruns. If you are using spigot plugins in your server to delete worlds, that must mean that your server itself is spigot.
However, all though I may not be correct by saying this, if you use that plugin to delete the world and then switch your server to vanilla before speedrunning, you may be allowed to do that. I am not 100% sure about this, but all I know for certain is that the server where you speedrun may not be run on Paper, Bukkit, or Spigot.
Since it's a LAN world and not a server, the admin (or the person hosting) must show in their video the random generation of the world, them entering the server, opening to lan, etc... Basically the only difference is that instead of showing the player enter the server from the menu screen, it has to show the generation of the world (and the blank seed generation input) from the menu screen, similar to the requirements of a solo speedrun.
Just download optifine! Badlion client has optifine in it but also has mods which are banned in speedrunning. You can find it on the official optifine website and it is quite easy to download.
In the rules it says it is not, but it would greatly help the moderators analyze and time your run.