There are two versions of this work, written in 1945: one for strings, and another for mixed chorus.
Thesis: Gerling, Fredi Vieira, and Heitor Villa-Lobos. 2000. Performance anaylsis and analysis for performance: a study of Villa-Lobos's Bachianas brasileiras no. 9. Thesis (D.M.A.)--University of Iowa, 2000.
Thesis: Otero, Stephanie. 1999. Heitor Villa-Lobos' contribution to the national music of Brazil with analyses of Bachianas Braseilieras no. 1 and no. 9. Thesis (M.M.)--New Mexico State University, 1999.
The choral version is dedicated to Aaron Copland.
Choral version: SMATBB
String orchestra version: violins, viola, cello, bass
This comprehensive listing of Bachianas Brasileiras scores from the Major Orchestra Librarians' Association website contains lots of useful information.
Choral Version:
DVD:
Premiere (orchestral version): 17/11/48, Rio de Janeiro - Theatro Municipal. Quinteto de Cordas da Orquestra Sinfônica Brasileira; Eleazar de Carvalho, conductor
Premiere (choral version): 25/10/75, Rio de Janeiro - Sala Cecília Meireles. Coral Artis Canticum; Nelson de Macedo, director
Most of the performances in the Villa-Lobos Concerts database (77 as of August 2009) are for the string orchestra version, though the choral version is becoming more popular.