just an FYI, the S9 is not profitable and barely produces any sats. i only use them to heat my house in the winter or at random times during the warmer months if my basement is too cold.
that doesn't mean that it's not worth it to buy one for $150 to learn and play around though. use it to figure out how to manage sound and heat and see if you want to get into something a bit more cost effective and also pricier.