...which can be rented in the baggage claim area of each terminal. All Airtrain stations are elevator-accessible, and train doors and interiors are designed for easy access and cart storage.

NB - there are two service loops. Trains on the inner loop serve all terminals. Trains on the outer loop will stop at Terminals 5/6, 7 and 8/9 (your stop) and then continue off-airport to parking and connecting train service. You should take whichever train arrives first.