Just point your bitcoin miner to a BCH pool and mine away
Can you tell us in more detail?
You can take your Antminer s9 or any other SHA-256 miner and point it to a pool that has Bitcoin Cash available to mine. This would be one as an example
https://pool.bitcoin.com/index.html?code=WjNstLYou need to create an account and then choose which stratum server to connect to. You can select the auto switching stratum server which will mine bitcoin cash or bitcoin depending on which one is more profitable to mine at that time, or you can just set it directly to mine bitcoin cash.
Cheers