We don't have synonyms for cadie yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are cadre, caddie and cadge.
(n) :
(historical) Alternative spelling of caddie (“a gentleman who joined the military without a commission as a career; a young man; a person engaged to run errands such as carrying goods and messages; specifically, a member of an organized group of such persons working in large Scottish towns in the early 18th century”). [(Scotland) (also attributively, obsolete) Synonym of cadet (“a gentleman (often a younger son from a noble family) who joined the military without a commission as a career”).]
(n) :
(historical) Alternative spelling of caddie (“a gentleman who joined the military without a commission as a career; a young man; a person engaged to run errands such as carrying goods and messages; specifically, a member of an organized group of such persons working in large Scottish towns in the early 18th century”). [(Scotland) (also attributively, obsolete) Synonym of cadet (“a gentleman (often a younger son from a noble family) who joined the military without a commission as a career”).]