One can shout, welcoming European traveller (9)
I believe the answer is:
itinerant
'welcoming european traveller' is the definition.
'itinerant' can be an answer for 'traveller' (itinerant is a kind of traveller). I am not sure about the 'welcoming european' bit.
'one can shout' is the wordplay.
'one' becomes 'I' (Roman numeral).
'can' becomes 'tine' (I am not sure about this - if you are sure you should believe this answer much more).
'shout' becomes 'rant' (I've seen this in other clues).
'i'+'tine'+'rant'='ITINERANT'
Can you help me to learn more?
(Other definitions for itinerant that I've seen before include "Nomadic" , "Travelling around" , "Person who moves from place to place" , "Nomad" , "(Person) on the move" .)