Modern Vespa

I would rather get a 12v raw car power outlet than a ready made USB port that will become outdated as the phone chargers update.

What car power outlet kit do you recommend in the front close to the handlebar?

Is there such another port that can connect under the seat or to the rear luggage rack for other devices that I may want to charge as well?

Call Scooter West

I got one from scooter west also, easy install.

Yes, got mine from Scooter West also.
https://www.scooterwest.com/gt-gts-gtv-power-plug-gtspp-bk.html

I also bought a conversion that lets me use the same plug with my Battery Tender to charge my GTS 300.

This, just like the cigarette lighter socket on a car, is an unregulated socket. It will see the voltage at the battery which could be up to just under 15 volts. You may want to protect your electronic device using a regulating adapter which pins the voltage at exactly 12. Although of course most people will plug in a usb adapter anyway and that is regulated to 5 volts. There are a few tablets etc. taking a twelve volt input but these shouldn't be connected directly unless the manufacturer specifically allow it ( e.g. Sat Nav devices which may be designed for direct connection to vehicle supply).

Where do I get a regulated adapter from?

Honestly, there's no need! Any device rated for "12V" will work fine from a vehicle's nominally 12V system.

Maplins used to sell these in the UK with a switchable choice of output voltages and a variety of output plug sizes. Try RadioShack in the US if they are still in business there. I would reiterate that if a device is designed to run from the cars power supply it will be fine but if its not you should at least check with the manufacturer.

ScooterWest has exactly what you are looking for to install in the left side knee pad.

Drill a hole in the knee pad at the location you choose, and the tap into the unused alarm block that is already there.

Easy Peasy! I think there is even an install video available to walk you through it.