You're looking at the `dev` docs, which apply to the unstable nightly version of django currently in the official django git repo.

Django is currently on 1.6 (which was released a few weeks ago) and their point cycle is every 8-ish months, with one long term release every few versions (1.7 will probably be the next long term release)

The eventual replacement for `get_cache`, `caches`, will not be in a stable/public release until 1.7 is released in 8ish months and due to various big changes in 1.7 I'd imagine the adoption rate of 1.7 will be rather slow for existing projects.

So 1.9 is a few years out.