I dont know too much about them, but going on the thinking that side shoots will readily develop from a stem on the horizontal or a 45 deg angle. If your Kiwi has still got some flexability in the main stem, can yuo bend it over........kinda like a cordon.
This is only a guess, on the other hand because you only planted it this spring, it may well need to develop a stronger root system before the top growth branches out......
Im interested now.......