The bacteria are probably eubacteria because they live on common plant leaves.
Archaebacteria living in extreme places(like the thermophile bacteria that in a volcano) while eubacteria lives in normal places. Leaves of common houseplants is not an extreme location, so Archaebacteria is less likely found there. Both eubacteria and archaebacteria could be autotroph or heterotroph, so the information cannot be used to conclude anything.
