[AznDrift]

a car power converter from 12V to 9V and from 5A to 4A, an adaptor where you can stick it into the lighter socket?

Thanks!

[Overseas Auto1]

call the revscene sponsor JP Cellular, Jacob Poon.

[noventa]

^
is that a trick where you go, "Hi, May i speak to mr. Poon?"

[Soundy]

What do you need to power at 9V? A lot of devices that call for 9V will work fine at 12V.

Also, you don't have to reduce the current - a device will only draw as much current as it needs; you only need to ensure the adapter can provide as much or more current than the device needs.