All that's been said is good advice, I would add that you'll want to evaluate the suspension pieces you have that need help, and where you want to end up. Unless you want to spread your expenses over a several year period, while using the car, rebuilding to stock configuration first might mean you'll be spending money twice when you do the lowering.

Here's one company that focuses on this era Ford; www.jamcosuspension.com

Oh, and that does look like a 9".