boosterish
adjective
boost·er·ish ˈbü-stə-rish 
: typical or suggestive of boosters or boosterism : marked by or showing extremely or excessively enthusiastic support for something
Beginning in 1943 … American musical theater proffered an upbeat nationalism that mirrored the country's increasingly boosterish mood.
Carol Troyen, American Art, Summer 1993
Carol Troyen, American Art, Summer 1993
Word History
First Known Use
1939, in the meaning defined above