Press agitated about hotel serving watered-down drinks (9)
I believe the answer is:
spritzers
'watered-down drinks' is the definition.
(a spritzer is a wine and soda water drink)
'press agitated about hotel' is the wordplay.
'agitated' indicates an anagram.
'about' indicates putting letters inside.
'hotel' becomes 'ritz' (I've seen this before).
'press' is an anagram of 'spers'.
'spers' going around 'ritz' is 'SPRITZERS'.
'serving' is the link.
(Other definitions for spritzers that I've seen before include "Drinks of wine mixed with a sparkling water" , "booze" .)