Former taxi company worker, for one, is high-spirited (9)
I believe the answer is:
exuberant
'one is high-spirited' is the definition.
(synonyms)
'former taxi company worker' is the wordplay.
'former' becomes 'ex' (prefix meaning former or onetime).
'taxi company' becomes 'uber' (I've seen this before).
'worker' becomes 'ant' (worker is a type of ant).
'ex'+'uber'+'ant'='EXUBERANT'
'for' acts as a link.
(Other definitions for exuberant that I've seen before include "Joyously unrestrained" , "High-spirited" , "Elated" , "Vivacious; effusive" , "Enthusiastic" .)