This is a question best asked to Microsoft, not here. No one I know of who posts here regularly is an MS employee, let alone someone in their sales division who will know the strictures of licensing.

To my knowledge, you have connection limits on developer addition. You can't violate those limits, so as long as you're working within them, I think you can use it for development. But, that's just me, some dude on the internet. Contact Microsoft for real answers.