Someone other than me about to tour pitch where Arsenal play (9)
I believe the answer is:
islington
'where arsenal play' is the definition.
(Arsenal FC's ground is in Islington, London)
'someone other than me about to tour pitch' is the wordplay.
'someone other than me' becomes 'not I' (not I - someone else).
'about' is a reversal indicator.
'to tour' indicates putting letters inside (to tour can mean to go around).
'pitch' becomes 'sling' (I've seen this in another clue).
'noti' written backwards gives 'iton'.
'iton' going around 'sling' is 'ISLINGTON'.
(Other definitions for islington that I've seen before include "part of London?" , "Area of northeast London" , "NE London borough" , "London suburb" , "part of capital" .)