Plenty of little 12v to micro USB adapters on Amazon or ebay.
And yes, I have streamed data via WiFi
If using the adapter though....it's nice for it to have a permanent power supply, otherwise the router takes maybe 20-30s on power up to start doing its WiFi thingy. Which can be annoying.
If you leave it on all the time, you're always ready for an instant connection to the ecu. Albeit with the only downside of a power drain.