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As with so many things, you aren't going to be able to figure this out definitively until you get there. Starting point? ISO 3200, f/2.8, 1/500. Give it a try and see how it looks. Another approach is to find something neutral on the field of play and spot-meter off of it in AV mode at f/2.8 and your ISO set at 3200. See what you get.
As for WB, if the light is consistent, you could try a custom WB, but so often the color of the light varies, in which case you try to find a Kelvin temp. that is an average or you rely on AWB. If there are any newspaper shooters there, ask them how they handle WB. (It can be helpful to talk with someone who has shot often at a particular venue to learn about some of the idiosyncrasies of the light, and at a high school field, a newspaper photographer is your most likely frequent shooter.)