Enthusiastic blue exercising, right on time (9)
I believe the answer is:
ebullient
'enthusiastic' is the definition.
(I've seen this before)
'blue exercising right on time' is the wordplay.
'exercising' indicates an anagram (letters exercise or move around).
'right' becomes 'lien' (legal right).
'on' says to put letters next to each other.
'time' becomes 't' (abbreviation).
'blue' is an anagram of 'ebul'.
'ebul'+'lien'+'t'='EBULLIENT'
(Other definitions for ebullient that I've seen before include "Overflowing with enthusiasm" , "Full of cheerful enthusiasm" , "Joyously unrestrained" , "Libel tune (anag.)" , "bright and breezy?" .)