Definitely a pfd and have it on - not something to be put on after you are in the water. I dumped once and when it happens it happens so fast.
I try to keep things to a minimum, since even though I have hundreds of lures, only a handful can be counted on to produce. Take the ones you can count on and a few you might want to experiment with.
I have a sit on top 10' wilderness tarpon. If you use a seat pad make sure it's a thin one, as you don't want to raise your center of gravity too high for stability reasons on some kayaks.
I usually take 2 or 3 poles. I have 2 rod holders in front of me so I can see when I'm trolling if I get a hit.
Poles are 6'6" down to 5' depending on what I'm fishing for.
I take a few bags of soft plastics and a plastic box for a few spoons, spinners and jigs. Needle nose pliers and a net with rubber mesh, since hooks won't snag up in this as much.
Here's a tip that may save you some gear - get some foam insulation, the type that comes in 4' lengths that is used for copper water lines. Cut it to 6" lengths and put it on your rods above the handle. If your pole goes in the water it will float it enough for you to grab it. You may need a little more or less than 6" depending on the weight of your rod & reel.
Have fun and enjoy the fishing, it's definitely a great experience getting towed around by a good size fish.