There isn't anything kivy specific that I know of. But you should just be able to use a standard python autocomplete sublime text library. I currently use
https://github.com/DamnWidget/anaconda and it works quite well, but it is pretty cpu intensive sometimes. There is also
https://github.com/srusskih/SublimeJEDI, which anaconda actually uses for the autocomplete feature, as well as go to definition, I believe.