The most common and most likely answer to this crossword clue is the 9 letter word EXUBERANT
I've seen this crossword clue in The Times
E
X
U
B
E
R
A
N
T
More clues leading to the result EXUBERANT
- Vivacious former queen?
- Elated over German worker supporting former partner
- Once a mighty worker, full of life
- Old taxi worker in high spirits
- Former taxi firm worker possibly in high spirits
- Jolly old soldier, say, catching cab
- High-spirited former soldier grabs cheap taxi
- In high spirits from energy extra bun produced
- Former cab-firm worker is full of joy
- Sparkling beer and tuna cross in blender
Buddy explains!

The straight part
We know that "Vivacious" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case vivacious = exuberant.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does EXUBERANT mean?
EXUBERANT adjective- (of people) Very high-spirited; extremely energetic and enthusiastic.
- (of things that grow) Abundant, luxuriant.