MyBB Community Forums

Wondering if I can create a bot to make automatic posts, and on the forum page there's a javascript option to vote yes or no, that gets automatically sent to another server

I wouldn't let normal users make javascript... Just wondering if it's possible somehow for an admin/bot to do it? 

You should be able to do so with this plugin:
https://community.mybb.com/mods.php?action=view&pid=16

If you want to write automatic posts, why not write a PHP script?
In regards to option for yes or no, you can use XThreads to add a thread field for such case and add a simple php script for yes response that will send data to another server.