Is it possible to have Captivate 9 read text captions that utilize variables (such as learner's name)?

No, that is not possible. Reason is that contrary to normal text captions which are 'ready' when the course is launched, text containers that have included variables are dynamic text, which will be generated On Runtime. If you try to use a screenreader, the name of the variable will be read, not the value that the variable has gotten On Runtime, which can be changed at each moment due to a new action.

That sneak peek from MAX was about the CC, not about Captivate.

Although... It might be possible sooner than you might think. Watch this video sneak peek from Adobe MAX https://youtu.be/I3l4XLZ59iw

If you mean read as in "read out loud"? I don't think so, however you can display the variable for a student's name collected from a learning management system in a text caption. The system variable you can use is cpQuizInfoStudentName. No guarantee that all LMS will supply this information to your Captivate course though.

Alternatively you can add a text entry box on one of your opening pages and have the student type in their own name, store it to a variable of your choosing and display it onscreen from time to time. This will add some level of personalization for the student.