Do you have to enable a playbar to be able to turn on and off Closed captions?

You posted twice a similar question, but here the title is totally different from the question? Do you want to turn on/off Closed Captioning without using the playbar, you can use an action toggling the system variable cpCmndCC. Default value for that variable is 0, which means CC is not on. Set it to 1 and CC is turned on. More infor:

System variables in Captivate 8/9 and 2017 - Captivate blog

You can create a toggle button:

1 action = 5 Toggle Buttons - Captivate blog