Vegetable that's popular stocked by hotel (9)
I believe the answer is:
aubergine
'vegetable' is the definition.
(I know that aubergine is a vegetable)
'popular stocked by hotel' is the wordplay.
'popular' becomes 'in' ('in' can mean trendy).
'stocked by' indicates putting letters inside.
'hotel' becomes 'auberge' (type of inn or hotel in France).
'in' inserted into 'auberge' is 'AUBERGINE'.
'that's' acts as a link.
(Other definitions for aubergine that I've seen before include "Vegetable strangely found in a burgee" , "Fruit cooked and eaten as a vegetable" , "I agree bun could become a strange vegetable" , "I argue, Ben, that it's a fruit" , "Vegetarians might order this" .)