

There a lot of numbers higher than the 9Gs that are safe-ish and reasonable-ish for human drivers/pilots to experience regularly. A big bag of water with bones inside that likes to breathe doesn’t take well to high levels of acceleration, eg. really fast turns.
F1 maxes out around 6/7Gs, but they’re not solely limited by tire friction, they’re effectively upside down planes that use their airfoils to get more traction. A lot of the difference is sideways Gs are harder. A pilot getting pushed down into their seat while banking through a turn can have more control than a driver getting pulled to the outside of the turn.