I'm completely new to this field so I'm still feeling my way around things.

Is it normal protocol to let your potential employer know your member number in your national coaching association? What about the member number of the national sports association?

I'm thinking it would be easier for him to verify my qualifications in this way but it may also be private information I'm supposed to keep to myself. To be honest, I don't mind either way but I want to do things appropriately. Which is it?

I would think that if your potential employer wants to know this and/or needs to know this - it will be asked of you.