You need to provide 3.3V power to the Bluetooth module and a Zener diode + resistor combination is fine for that, as long as the components are chosen correctly.
However, you also need to have level shifters on the input/output lines of the module and the Zener/resistor combination won't work for that purpose. For those lines I would suggest a bidirectional level shifter board like this: https://www.sparkfun.com/products/12009
Or, use a 3.3V Arduino for everything.