Bags of support with crowds (9)
I believe the answer is:
backpacks
'bags' is the definition.
(backpack is a kind of bag)
'support with crowds' is the wordplay.
'support' becomes 'back' (to back is to support or endorse).
'with' means one lot of letters go next to another.
'crowds' becomes 'packs' (packing is a kind of crowding).
'back'+'packs'='BACKPACKS'
'of' acts as a link.
(Other definitions for backpacks that I've seen before include "Knapsacks, rucksacks" , "Travels" .)