"We play together."
Translation:Kami bermain bersama.
True! It is just that from the sentence "We play together." much can be inferred, read into the sentence, lacking discrete context. For me, thus, either seems a suitable reply until the context is given. From your example, I definitely accept and agree that "kami" is correct. On its own (not to "beat a dead horse"), it could be reported speech - or, it could be: direct speech.