SST sounds alarming, yes-- but--
that's exactly what the school used when we weren't sure whether to do an additional skip with DD in 6th grade.
So as long as the players involved are genuinely interested in doing something that works FOR THE STUDENT (as opposed to moving a 'problem' to be someone ELSE's problem, if you catch my drift there)...
it can be a positive thing, and it may not have to even go any further if "normal" interventions are enough... and honestly, there isn't any law that says that the interventions normally written into 504/IEP plans
cannot be offered as placement options/interventions for any student... it's just that they HAVE to be offered to eligible students who have status as QID's (Qualified Individual with Disability).
It does sound as though what she ACTUALLY could use is an academic setting 4y or so beyond what she has... but with a physical setting that keeps her in age-appropriate expectations for behavior and emotional regulation. I'm not sure how you get that. Well, I know how we did it, but my DD didn't have the difficulty with emotional regulation to this degree.
Any standard placement is going to chafe, probably-- you just have to figure out least-worst. Look at it this way, at least the other people involved may know of options that you don't.
