I agree with Villavic, Pisac market and ruins and Ollantaytambo ruins is enough for one day. Stay at Ollantaytambo on Sunday night, that's where the trains to Aguas Calientes leave.

I think you have enough time in Cuzco to see all the relevant sites and could, if there would be need, cut 1 day, but given the fact that September is not the best month for Lima, but a good one for Cuzco, I would rather spend 1 day too much in Cuzco than in Lima.