Hanging around's tiring Leo out (9)
I believe the answer is:
loitering
'hanging around's' is the definition.
('loiter' can be a synonym of 'hang around')
'tiring leo out' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'tiring'+'leo'='tiringleo'
'tiringleo' with letters rearranged gives 'LOITERING'.
(Other definitions for loitering that I've seen before include "Hanging around or lurking" , "Lingering" .)