Doctor gets air circulating between runs (9)
I believe the answer is:
registrar
'doctor' is the definition.
(I've seen this before)
'gets air circulating between runs' is the wordplay.
'circulating' is an anagram indicator.
'between' means one lot of letters goes inside another.
'runs' becomes 'rr' (I've seen this in other clues**).
'gets'+'air'='getsair'
'getsair' anagrammed gives 'egistra'.
'egistra' put into 'rr' is 'REGISTRAR'.
(Other definitions for registrar that I've seen before include "Wedding recorder" , "Recorder of births, deaths and marriages" , "Record keeper - hospital doctor" , "Mid-ranking doctor" , "Official recording births, deaths and marriages" .)