Came across Ted welcoming partygoers (9)
I believe the answer is:
traversed
'came across' is the definition.
(I've seen this before)
'ted welcoming partygoers' is the wordplay.
'welcoming' means one lot of letters goes inside another (in sense of 'inviting in').
'partygoers' becomes 'ravers' (people attending a rave).
'ted' enclosing 'ravers' is 'TRAVERSED'.
(Other definitions for traversed that I've seen before include "Went over" , "Travelled across zigzag course" , "Crossed" , "passed over" , "Came across" .)