The plugin does not recognise that I'm admin, so for example when I do /kid add test I get "You must either be admin, or have the admin permission to use that command". If I give myself the kit.admin permission then it works, but I shouldn't need to if I'm the server owner/admin, right?

wrong. you grant yourself admin permission. other plugins also require you to do the same even if you are admin /owner. it makes it easier to check how they work as a player if you can revoke that permission .

If that's the case, then the wording on the plugin page is confusing:

• kits.admin - Allows non-admin players to use the admin commands

JimDeadlock

If that's the case, then the wording on the plugin page is confusing:

• kits.admin - Allows non-admin players to use the admin commands

... implies that admin players don't need it.

its up to you, you seem to have solved it so i will leave it to your discretion