There are, that I am aware of, 4 main entries in the computer guided interval training space. PerfPro and PeriPedal are 1 time purchase software applications that are about $100, TrainerRoad is a subscription model that costs $10/month. There is also iMobileIntervals that is far less at $5.99 one time purchase. All of these will pair with your Kickr and control it in erg mode and allow you to plan and conduct workouts. I personally use TR. I have used it for a few years even before I got my Kickr. I tried iMobileIntervals but found it to be buggy and underfeatured. I believe PerfPro and PeriPedal offer 15 or 30 day trials. I have been meaning to try one of them out but haven't gotten to it yet. The newest release of Golden Cheetah has a module that can control the Kickr in erg mode but I could never get it to work. It wouldn't pair with my Kickr, so I could never actually try to use it.
If you try one or more of these please post your experiences. It would be good to get a thread going on the relative merits of each. Others are going to have the same questions.