Observe judge with personality (9)
I believe the answer is:
celebrate
'observe' is the definition.
(I know that observe can be written as celebrate)
'judge with personality' is the wordplay.
'judge' becomes 'rate' (rating is a kind of judging).
'with' means one lot of letters go next to another.
'personality' becomes 'celeb' (celebrity personality).
'rate' after 'celeb' is 'CELEBRATE'.
(Other definitions for celebrate that I've seen before include "Stage a special festivity" , "Mark special event with festivities" , "Honour; make famous" , "Have a party to mark a happy event" , "Have a party in honour of" .)