If your alkalinity and not the pH is 9 (9 would be very high for pH), then that's extremely low for alkalinity and below what's generally considered the minimum threshold for fertilizer to be effective, so you would need to add lime to make the fertilizer work.
I've had the best luck with liquid fertilizer that's a 10-50-0 formulation; formulations similar to this are sold under several different brands; the one I buy is called Tackle Buster and I get it from my local co-op, about $27 per 2.5 gallon jug, and a gallon does an acre. You will need to dilute it, which can be accomplished a few different ways ranging from pouring the liquid into the prop wash of a small outboard (the best method) to spraying it onto the surface with a garden sprayer like one would use for a herbicide application to diluting it 10:1 with pond water in a five-gallon bucket and splashing it onto the surface of the pond.
If you start fertilizing in mid-February or the beginning of March (I start in March but I live in TN, don't know what part of TX you're in), assuming you lime first with a ton of lime per acre, you should get a good plankton bloom by the second (which should come two weeks after the first) or third application of fertilizer. The FA won't be at full strength by then, so before it has a chance to take off you'll be blocking out its lifeline, and it will die. If your soil were naturally fertile, you possibly could fertilize even after the FA got going good, as I've done this more than once and initially for a couple days the FA grew more but as soon as a good bloom occurred the FA died off; but seeing as you haven't fertilized before, you would want to get ahead of the FA by fertilizing early. But if your alkalinity is 9, liming first will be crucial to make the fertilizer work.
