What are the key considerations when choosing a road bike cassette for a 9-speed bike?

When choosing a road bike cassette for a 9-speed bike, key considerations include the number of gears, gear ratiOS, and compatibility with the bike's derailleur. Make sure the cassette has the right number of speeds (9-speed in this case) and that the gear ratiOS suit your riding preferences. Additionally, ensure compatibility with your bike's derailleur to ensure smooth shifting.