Power consumption figures will vary with your PSU's efficiency, the ambient operating temperature and the accuracy of the power meter.
You will need an ATX PSU. Bitmain recommends the APW3++ for the S9 miners. It cannot power more than one miner.
There are 3 PCI-e connectors for +12V DC input on each hashing board and all 3 need to be connected to the PSU for the hashboard to operate. Do not connect more than one PSU to the same hashing board!
Separate power supply to control board: there is one additional 6pin PCI-e connector on the IO board which must be connected to the PSU to get power. Be sure to power on the miner only after all the 10x PCIE connectors are connected to power supply.