I just really want to see these two interacting. Canonically, Bender speaks binary, so they'd be able to communicate. If you want to make it shippy that's fine too (Bender has had relationships with suicide booths, starships, and vending machines. A spherical robot would be positively normal for him).

+1000 if BB-8 starts saying "bite my shiny metal ass" to Poe whenever Poe tries to make him do something he doesn't want to do.