'Idol' Boy Scout ADVANCES ... to Eagle Scout

The 18-year-old Boy Scout who got DENIED on "American Idol" last night finally got some good news -- he'll be promoted to the rank of EAGLE SCOUT tomorrow!!!


TMZ has learned ... Christopher Cordeiro -- who bombed during his rendition of "My Way" -- had a back-up life plan all along ... and interviewed with the Eagle Scout Board of Review back in November.

Cordeiro was a hit with the Eagles ... and will officially get his promotion tomorrow during a special ceremony in his home state of New Jersey.

Always be prepared ... for "Idol" rejection.