Mazda is bringing the rotary engine back in 2022.
But not in an RX-9. It will be used as a range extender in the battery electric version of the MX-30. This is actually an optimal use for a rotary engine. They are small and light, so they are easy to package in the car. And since it is off until it is needed to charge a depleted battery, no worries about the smog or the horrible gas mileage that killed it in 2012. And since it won't be powering the wheels, it can be controlled to only run in its most efficient sweet spot, minimizing emissions and fuel usage.
Confirmed! Mazda MX-30 Gets a Rotary Range Extender