Cultural and linguistic evidence concerning the origin and distribution of enset culture seem to point generally in the same direction. Enset was part of a widespread and ancient system of cultivation of vegetative crops formerly distributed much more widely through the Ethiopian highlands. The main cultivators of enset were Omotic-speakers, though it was probably adopted early by some groups of Cushitic-speakers. However, when the Ethio-Semites entered Ethiopia bringing seed agriculture and the plough, enset and other root crops such as yams (Dioscorea spp.) and the Labiates (Coleus spp.) were pushed into residual cultivation, except where the terrain was so highly dissected that ploughing was effectively impossible. In this situation, notably in the southwest, the Gurage Semitic-speakers adopted enset and it became central to their production system, permitting the expansion of population to levels such that no other crop would support comparable densities in similar terrain.
Having just blasted through some of Blench’s work I can tell you that Cushitic speaking languages essentially date to the Neolithic as they have root words for sheep and goat, that wouldn’t have arrived until at least 7,000 BP in that area, and probably a lot later. This would suggest a later domestication date for enset, sometime around 5,000 BP.