PDO exception "could not find driver" means either the DSN in your PDO config doesn't define (the correct) driver, or the driver is not installed in your config.
If it does work from a webpage, but it doesn't from the commandline, chances are that your installation uses a custom php.ini location for the web SAPI, causing php-cli to run with a php.ini that misses everything, including PDO drivers. Complete packages like WAMP and MAMP (for Mac) are notorious for this problem.
To find which ini file is used, use the php_ini_loaded_file() function. Echo it out in a View, and use the oil console to check it's value on the commandline. I'm pretty sure you'll find them to be different.
No, you need to use the oil console (php oil console) and then type the function name.
The console gives you an interactive PHP commandline in which you can type any PHP command, access any class in your app, run a DB::select on a table, etc. It's a very handy tool to use as a backdoor in your application, for debug purposes.
The error message is very clear: PDO Exception "could not find driver"
If you Google for it you get tons of replies telling you all the same: either your DSN is wrong, or a PDO driver is not installed.
And the fact that this happens with your code on all platforms suggests it is not a problem with the platform, but with your code. So either a DSN error, or incorrect setup of your db.php config files.
I run Fuel on Windows 2012 server with WAMP, especially for compatibility testing. And that works without problems.
You keep on complaining, but you don't give any information about your setup, your configuration, exact errors, what you have tried, and whether or not it is fixed. And I've asked for that repeatingly.
Not all PHP distributions have all PDO drivers installed by default, and not all installations use the same php.ini for the php SAPI and php-cli.exe.
I said it before, and I can only repeat myself: PDO Exception "could not find driver" means the driver is not installed, or your php interpreter uses a php.ini that doesn't load the driver.