The label should have application rates. They're often listed as quantity of product per acre (43,000 sq ft), applied in minimum of X gallons of water. You'll want to do the math to break that down to 9000 sq ft.

I don't know if you can use a wettable powder in the "dial a spray" hose-end sprayers, but I doubt it. I do know that they're notoriously inaccurate, in any case. And too much Dimension can definitely be a bad thing. I think you want a sprayer. And you'll need to calibrate it to your walking pace & pressure in the tank. A cheap sprayer will be hard to monitor the pressure (and thus liquid output).

Realistically, It may be easier to return the powder/exchange for granular. Especially since you probably want to get it down pretty soon (depending on your location).

Thank you! I returned the water-soluble bags and bought the granular formula (Lesco's Dimension .21% Plus Fertilizer). I now have to figure out what setting to set my Scott's Edgeguard spreader. I am going to look at Lesco's website.
I am a mom who has never done this before.
Thanks again!