This hoverboard doesn't have any unlockable upgrades.
9th Birthday is a limited hoverboard in Subway Surfers exclusive to . Like any other hoverboard, it will protect you from crashing for 30 seconds. When crashed, the board will explode and recharge for a few seconds before it can be used again. It has the appearance of a birthday present. This is a free gift to celebrate Subway Surfers 9th anniversary.
It's a blue and light blue-stripped board with a yellow bow wrapped around it.