So my question is: should I just stick with this flying instructor until things are "right" or am I wasting my time?
As you describe things you are certainly wasting your time. If progress in the circuit is not being achieved then it is time to move on through the syllabus. This will increase your confidence and, of course, will continue to develop your flying skills. Continuing unsuccessfully in the circuit will only develop deep seated negative phobias within you and therefore it is wrong.
A common cause of an individual struggling in the circuit is due to the early hours being rushed and so left incomplete. The circuit is not the place to learn to fly. It is a place when for the first time you apply the learned skills. 8-9 hours circuit bashing without progress is too much and tells me the early hours were rushed and not fully understood. So, in terms of the syllabus, if the pre-circuit work was poor or skimped then you need to revise these until complete. Following this move on to the post circuit work, you have done enough 12/13 for the time being. A return to the dedicated circuit work should be when it is known to be appropriate and your confidence has been restored, but not before.
If it is how you describe it then you must change the instructor. As already advised speak to the CFI/Head of Training about all this for a planned resolve.