I've built a car charger using one of those CPT modules, out of curiosity as much as anything. They are pretty good, cheap buck converters. The noise on the output of mine is within the spec for USB charging. It is not isolating, so 12V ground is connected to 5V ground - which can cause noise if it's plugged into the stereo with an aux jack.
The tricky bit is "fast-charging" your phone. If you just provide 5V to a phone, using the power and ground wires in a USB cable, it will usually charge at 500mA. That's the same as when plugged into a PC, and it'll take a while. Most phones these days can charge at least four times that fast, if the charger supports it. They check whether the charger supports it by looking at the connection of the data wires in the USB cable, and sometimes the connection of the metal housing of the connector. There is a standard, but frustratingly many phones don't use that standard.
If you have one type of phone/tablet you want to charge you can usually look up how to wire the data leads to get fast charging to work for that type. Most brands use the same pattern across all their devices, but Apple use different patterns for different devices. You can also get ICs which detect which type of device is connected and pretend to be the right type of charger, but that's quite complicated for a beginner.
Or, if you want to do it the simple way, buy a charger with the fast-charging features, connect it to your cables, and hot-glue it out of sight behind some trim.
Oh, and whichever way you do this, work out which fuse in the fusebox feeds those cables and swap it for something appropriate - a wheelchair lift would probably take a lot of current, where one of these modules only needs about 1.5A max.