I've grown them in 12" and 16" containers.
They reached a bit over 6' tall.
Obviously not as big as when planted in the ground - but still impressive.

I've been growing Casor Oil Bean plants for a few years on my rooftop deck. You won't have any issues with growing them in containers. However, a lower level of light will dramatically limit their size. One other issue to keep in mind is the wind. Be prepared to anchor the containers to your deck or railing. The wind will easily knock over the containers. The large leaves are also easily torn in a windy area. Have a great time growing them. I live in Chicago too and mine are already over 2 ft tall.

Take care, Pat