Charge for entrance to a first development undertaking (9)
I believe the answer is:
admission
'charge for entrance' is the definition.
(I've seen this before)
'a first development undertaking' is the wordplay.
'first development' becomes 'd' (mst letter of 'development').
'undertaking' becomes 'mission' (I've seen this in other clues).
'a'+'d'+'mission'='ADMISSION'
'to' is the link.
(Other definitions for admission that I've seen before include "Right to enter" , "A confessing" , "guilty revelation" , "for which one may be charged" , "Acknowledgement < of entry" .)