Joker upset rest after parking by taxi stand (9)
I believe the answer is:
prankster
'joker' is the definition.
(I've seen this before)
'upset rest after parking by taxi stand' is the wordplay.
'upset' is an anagram indicator.
'after' says to put letters next to each other.
'parking' becomes 'p' (abbreviation on road signs).
'by' means one lot of letters go next to another.
'taxi stand' becomes 'rank' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'rest' anagrammed gives 'ster'.
'p'+'rank'='prank'
'ster' put after 'prank' is 'PRANKSTER'.
Can you help me to learn more?
(Other definitions for prankster that I've seen before include "Practical joker" , "Wag" .)