With eight sides in National League heading for administration, first month has past (9)
I believe the answer is:
octagonal
'with eight sides' is the definition.
(an octagon has eight sides)
'first month has past' is the wordplay.
'first' says to put letters next to each other.
'month' becomes 'Oct' (abbreviation for October).
'has past' becomes 'agonal' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'oct'+'agonal' is 'OCTAGONAL'.
'in national league heading for administration' is the link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
(Other definitions for octagonal that I've seen before include "with certain sides" , "with quite a few sides" , "Having eight sides as in geometric figure" , "With many sides" , "Having eight straight sides" .)