Depends on your school so check the official policy. Early elementary is trickier. For our school and really district-wide since the central office has to approve the acceleration requested by the principal, the student has to test two or more years ahead. DS requested math acceleration in 2nd grade and was tested with 2nd through 5th grade tests plus an abilities typed test created by the district office.
Handwriting was one of several considerations that led me in favor of math acceleration but against a whole-grade acceleration. Handwriting should be considered but not necessarily a deal-breaker.
