@ Senpai - Oh~ You meant THAT outfit. Makes more sense but it would make hiding her chest even harder due to the lack of bindings. Maybe the school would allow her to skip? Failing that, I can just have her wear her training suit under it and say she thinks it's more convenient.
The researcher plan sounds good! Of course, students would wonder since he looks younger than them, but this is IS academy so I think they'll let it go
Now I need to justify him rooming with tatenashi
Would the students buy the "It's because she's the president" excuse?