The Collaborative International Dictionary of English v.0.48:

Caddie \Cad"die\, n. [Written also caddy, cadie, cady, and
   cawdy.] [See Cadet.]
   1. A cadet. [Obs. Scot.]
      [Webster 1913 Suppl.]

   2. A lad; young fellow. [Scot.] --Burns.
      [Webster 1913 Suppl.]

   3. One who does errands or other odd jobs. [Scot.]
      [Webster 1913 Suppl.]

   4. An attendant who carries a golf player's clubs, tees his
      ball, etc.
      [Webster 1913 Suppl.]

The Collaborative International Dictionary of English v.0.48:

Cadie \Cad"ie\, Caddie \Cad"die\, n.
   A Scotch errand boy, porter, or messenger. [Written also
   cady.]
   [1913 Webster]

         Every Scotchman, from the peer to the cadie.
                                                  --Macaulay.
   [1913 Webster]