Thank you.
First off, do you want a "car" that handles, or a "Pinto" that handles? If you want a "car", DON'T use a Pinto.
Please understand that there are ALWAYS trade-offs when it comes to performance. If you want to make the car "look" a certain way, it might not handle 'better' that way. It is ALL about balance, and what you want the car to do (I.E., things that help the car turn might hurt it get going from a standing start).
IMHO: Shorter/wider/sticker tires will give you more improvement than "lowering", or most any other SINGLE thing. Get the tires you plan to run BEFORE doing ANY "lowering" to the car. The stock rear springs have a rate that is too stiff, by removing leafs, you can dial them in and lower the car at the same time. Leaf springs are not easy to 'dial-in'. I reccamend fully disassembling, inspecting, cleaning, and the use of motorcycle chain lube between the leafs. If there is dirt or rust INSIDE them, it could cause binding that will hinder performance. If you tune-in the leafs, you should keep the weight of the car off the leafs if you plan to park it for any length of time. Performance shocks are important, but very hard to find for a Pinto; you might need to modify your car to fit ones made for other cars. A panhard bar is a very good idea, however, there is not much room under the car to put one so you will need to be creative; be sure it is installed on a reinforced part of the floor, AND that it is parallel with the ground at normal ride height. An 8" rear is more than enough, and IMHO, the 9" will just add extra weight. The use of lowering blocks in the rear should be kept to a minimum as they tend to induce wheel hop, and roll-steer; although roll steer can be helpful in setting up a car for a circle track (where the turns are ALWAYS the same), for most 'road' style driving it can be too unpredictable. A large front sway bar will help overcome the low roll center that Pintos have, provided the lower control arms angle DOWN from the crossmember, even if only slightly. Once they go the the other way (up to the wheels), you loose neg. camber very quickly. A front bar that is too big can flex the body, and a rear bar might need to be added to balance the car. Relocating the front lower control arm inner mount points UP 3/4" will improve the roll center, but it requires trimming of the arm and a little work to the crossmember. A full cage will help stiffen the chassis; a stiff chassis will help you dial in the suspension. Cutting coil springs will INCREASE their rate (stiffer) as well as shorter. For the car: lighter is BETTER. Get a full front end alignment after ANY change/changes to to car. Poly bushings are a great idea too.
Changes that you make will effect how the car handles, sometimes good, sometimes bad, but driving the car on a closed or private road after making changes will help reduce the chances of damaging you, others and your car.
If you plan to run or race in any form, check the rule books before making any changes to your car.
Again, a Pinto can not be MADE to handle as well as some other cars do in full stock form without MAJOR time and money. If your goals are to have a good handling "CAR", a Pinto should not be your first choice.
Bill