To calculate the time it takes for a tennis ball dropped from a height of 9 meters to hit the ground, we can use the formula:

```

t = √(2h/g)

```

where:

* t is the time in seconds

* h is the height in meters

* g is the acceleration due to gravity (approximately 9.8 m/s²)

Plugging in the given values, we get:

```

t = √(2(9 m) / 9.8 m/s²)

```

```

t ≈ 1.43 seconds

```

Therefore, it will take approximately 1.43 seconds for the tennis ball to hit the ground.