Thanks to all of you guys that tried helping but I got a fix myself for it. It turns out that the creator of Oil Derrick had released the hack privately to his friends and one of them leaked it. Anyway, when he found out about it he made a modification to the NEI mod to where it adds another layer of protection where it checks if you have OP before giving you creative mode. So No, this is not a plugin but rather a modification to a mod. If youre a server owner, message me for the fix link because I seem to not be able to put the link onto this post.