In my experience, when the personal histories of therapist and client overlap, if the therapist feels qualified to work with these issues s/he can use own experience to help empathize and keep it out of the client's time, as in not talking about it or at least talking about it very little, just maybe a detail to let a shy client know there are other people feeling the same way, for example.

There are also cases when a therapist might feel so overwhelmed with the similarities that the best choice might be not to work together. But indeed I do worry about a therapist freely talking about own abuse history in such a way that the overlap becomes an issue.

Now, maybe I misunderstand and that isn't your case. Maybe all Kashi said was mention a personal history of the same kind of thing you went through, without the details. I know I feel more connected in my therapy because I know my therapist practices martial arts, as I used to, or that at some point he wasn't very sociable either (I didn't use to be and even now I still need my alone time). But I think every therapist can choose what to share and what not to, and there's a difference between mentioning a hobby, preference, or even past heartache, and mentioning a history of abuse.

On the other hand, I think the most important here is how you feel. Do these similarities help or hurt the therapeutic relationship? If you have doubts, I suggest you bring them up. My personal preference and opinion is that a therapist's self-disclosure should help the client feel safe, open up, and work together toward the client's objectives, not confuse. But ultimately this is about what it's like for you and what you decide to do in this situation.

As for the driving phobia work, I personally wouldn't worry - boundaries do change in time. In my country we don't really have insurance for therapists (or at least most therapists don't and I've never met one who said they did) so every part of the treatment is based on each therapist's availability, courage, skills, confidence, etc. It may be that Kashi has grown to trust you and / or realized how much you do need to work on this.