Planner has no latitude - he shouldn’t throw a wobbly (6)
I believe the answer is:
potter
'he shouldn't throw a wobbly' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'planner has no latitude' is the wordplay.
'planner' becomes 'plotter' (plotter is a kind of planner).
'has no' indicates named letters should be taken away.
'latitude' becomes 'L' (abbreviation for latitude).
'plotter' with 'l' taken away is 'POTTER'.
Can you help me to learn more?
(Other definitions for potter that I've seen before include "One who makes ceramic ware" , "eg Harry or Beatrix" , "Creator of ceramics" , "Wizard Harry" , "One throws and moulds clay" .)