* A student who is upwardly mobile? This refers to a student from a lower socioeconomic background who is striving for a better life through education.
* A student who is optimistic and positive? There isn't a single perfect term, but words like "bright," "enthusiastic," or "motivated" might fit.
* A student who is moving up in a class or grade level? This student might be described as "promoted" or "advanced."
* A student at an "up" school? This is ambiguous; it requires clarification of what "up" means in this context (e.g., a prestigious school, a school higher up a hill).
* A typo? Perhaps you meant "up-and-coming" student, referring to a promising student.
Please clarify your question.