Some, but not all, 2 meter radios have a pin on the mic reserved for '9600 baud out'. If you connect to that and the signal ground, you should have all that you need insofar as audio from the radio is concerned.
Hmmm...guess not. What you will need is a service manual that lists out all the parts; from this you might be able to figure out what chip is used in the discriminator. It should be then possible to make a tap from this point to an unused pin on the mic jack. There's already a signal ground there.
Certainly would take some homework. It would almost be worth it to get an old scanner and put a tap in there. There are LOTS of places to find information on that on the web. Sri ! 73 Mike