Do you have a car with Bluetooth already built-in? If so, your phone would already have Bluetooth so no adapter needed. If your car does not have Bluetooth and you want to transmit your phone to your car stereo, then try something like this:
https://www.amazon.com/Nulaxy-Wirel...520&sr=1-3&keywords=bluetooth+car+transmitter
I actually bought this very unit and have yet to try it. LOL.
You can't be tracked with a phone number alone. But your phone number as it stands now may be attached to your name and address in so-called people search engines. It wouldn't matter if the phone number was a landline or cellular. And try as you might, opting out of these damn people search engines is a pain in the ass. I've opted out of at least 10 well known people search engine websites only to either see my data return or yet another damn website pop up with my Info. Then I found one website that shares your voter record and since that's considered "public" and for the public's consumption (BULLSHIT!) it can't be removed without a court order. You'd literally have to be a judge, actor, address, etc and talk to a lawyer to do it.
But no one can track your movements via your phone number alone unless they have installed a spyware App in your phone without you knowing it. Use a password, no face, fingerprint or swipe crap.
But to be honest, a lot of the Apps you install all ready grab your GPS data, so there's that. A mobile device is a marketer's wet dream come true. You can install a firewall App and control what Apps connect to the Internet, but be careful not to block anything you shouldn't. I'd also look at a Bluetooth firewall. You'd be surprised at its hacker potential. Especially with those phone charging stations you may find at hospitals or what ever. Plug your phone in, and your data is syphoned off. But not all charging stations have been hacked.