Base on current price of S9, the prices for S9 hashes should be 0.000225 BTC per GH/S when it first appear on market.
That is only dependable, at which price the first batch owners would be selling their S9 hashes. If I remember correctly on the first S7's hashes hitting the market, sellers were selling them around 10% above it's actual value.
It really depends on the price of hash AND the price of your power costs. In that regard, Bitmain wins against most home miners.