I get a plant like that every grow. Just a stragler. I dont worry about it, I just yank it. You have plenty of other great plants, why stress on it. Pull it. And it looks like you still have a couple weeks still till harvest.
I had the same problem, so I hung sticky fly paper over the sides of my 5g pots and they all get stuck on them. I had hundreds at first, now i change them out every couple of weeks with hardly any on them.
Place your trimmed buds on a cookie sheet spread out evenly. Set your oven to 125-140 degrees Fahrenheit (no hotter!). Leave for 10 minutes, remove for 5 minutes and turn buds. Repeat once more.
LST? Thats funny. It's going to outgrow that pc box and he's not going to know what to do. Waste of time and effort. Not flaming, just reality. I think he was Real High when he decided to go this route.