It's the first day of school for most of LA Unified, and while many students return to familiar classrooms, brand new schools will open at 17 sites. Among them are the 6 Robert F. Kennedy Community Schools at a complex on the site of the historic Ambassador Hotel, a $578-million project. Meanwhile, academic performance jumped in the district last year, according to scores released today. Will the trend continue amid budget cuts? And how will the news schools fare? Sharpen your pencils, class, school’s in session.