Hey Mike, I have an 07 K9 too and thought I would share some experience. I would definitely change out the controls, if they are original they are crap compared to the new ones that Derrick at HDM has made. I replaced mine a couple of years ago for the same issues you are having and haven't had a problem since. As far as the battery goes, I would get rid of that Duracell and get a Deka battery for it. You can buy a Deka or get a softail battery from the Harley Shop as they are made by Deka. I trust the experts on this site @MrWright,
@knothead @theinfamous and that is their recommendation for a battery on a BigDog. Some will argue but since i started using Deka batteries i have not experienced an issue one with any of my bikes. Matter of fact, I had this issue on my bagger a couple of weeks ago. Hit the start and nothing, turn signals wouldn't work nothing. Checked the battery and all looked good voltage wise, 13 volts but wouldn't start, no spin at all. The battery was a couple of years old so I went to the Harley shop and got a new one, put it in and she went right back to work. You are in the right place to get your K9 running again....best of luck