My opinion is that some due diligence will tell you very fast that the variety being hawked by Stark is not as reliable as other varieties available to grow. For example, in zone 7b and all of zone 6, Kanza, Hark, and Oswego would be better choices. The variety Stark is selling is listed as Silverback if you want to delve deeper.
Take a look at the pecan and black walnut threads and pull a copy of the pollination spreadsheet for more details. You will need pollination partners when planting most nut producing trees…
I think 6-9 years is a very reasonable estimate for a small pecan tree (1-2’) to begin producing. A friend of mine has a relative that started a commercial pecan orchard years ago and he said it took ~15 years before they were able to produce enough nuts to start selling commercially. My experience with two pecan trees is similar… ~10 years old and still not much production. They are definitely an investment!