My suggestion? Make the power easy to use compared to other 9th level powers - no save, no SR and then make the conduit a two-way street. You can only find someones real name by giving them YOUR real name.
Another aspect could be that the target doesn't KNOW that he knows your real name, but if he ever actually thinks about it (ie - damn, I wish I knew HIS true name), he'll find out that he does...
It makes it easy to get the real name of someone, and then scry on them to divine their plans for a while, and usually that won't let them notice that they can do the same to you.
However if you abuse it, you're likely to find that they'll go researching HOW it is that you keep scrying through their divinations, and then you're in trouble...