When is the gig up?

I am sure every parent goes through the conflict of how to handle the "truth" about the famous holiday icons like Santa and the Easter Bunny. In my situation, I thought that the kids would just hear rumors and come ask me for the truth and then I'd deliver the devastating news and give a pep talk about the spirit of the holidays and how we can keep them alive. So far, that is not the case and I am not struggling with whether I should approach my oldest child with the truth.

Benjamin is 9 and since he was old enough to write he has been leaving Santa notes on the tree. They started off mildly with questions like "how many reindeer do you have?" or "how are the toys made?" or "what are the reindeer's names?". These questions were a cake walk. My husband would write the responses with his left hand while I would look up the answers that we didn't know on Google.

Yesterday, I received his list of questions for Santa "so far". Let me tell you, I have some serious homework to do and I am scared to death. I don't know if even Google, Wikipedia or Jeeves can help me this year. The questions are so much more in-depth:
1. How do you get the materials for your toys
2. Do you have any children? and if so what are their names/ages
3. Where do you go on vacation?
4. What is your favorite healthy foods?

Keeping Christmas alive is so important to me but so is having the trust of my son. If I fabricate answers to his latest Santa test will he be so disappointed to learn that they came from me some day? If I tell him that there is no Santa will I have dashed his Christmas spirit? I know I am not the first parent to go through this anxiety and won't be the last. When is the gig up? Who calls the shots? Let it happen? or Make it happen? Hmmmmm.....where is the manual for this job?