Rugby players upend that man over tense tradesman (9)
I believe the answer is:
locksmith
'tradesman' is the definition.
(locksmith is a type of tradesman)
'rugby players upend that man over tense' is the wordplay.
'rugby players' becomes 'locks' (lock is a type of rugby player).
'upend' says the letters should be written in reverse (I've seen 'upending' mean this).
'that man' becomes 'him' (him refers to a man).
'over' indicates putting letters inside.
'tense' becomes 't' (abbreviation used in many dictionaries).
'him' enclosing 't' is 'htim'.
'htim' in reverse letter order is 'mith'.
'locks'+'mith'='LOCKSMITH'
(Other definitions for locksmith that I've seen before include "hairdresser?" , "laughing stock" , "Security expert" , "Maker of secure fasteners" , "Yale scholar" .)