Actually, if you're adventurous, you can clone it from github and build on your mac with bazel, but, your experience may suck in terms of performance (that's why it's not officially released yet). But, because you have an AMD, it will probably work well.

You would need to: bazel build -c opt plaidml:wheel plaidml/keras:wheel

and then

sudo pip install bazel-bin/plaidml/whl bazel-bin/plaidml/keras/whl