It is difficult to determine the exact distance a 9mm bullet will travel in a straight line as it depends on several factors, including the type of gun, the angle of firing, the bullet weight and design, the altitude, the humidity, the temperature, and the wind speed and direction.

In general, a 9mm bullet can travel up to 1,500 meters (4,921 feet) in a straight line when fired from a handgun or a submachine gun. However, the bullet will lose velocity and energy as it travels through the air, which will cause it to drop and lose accuracy.
When fired from a rifle, a 9mm bullet can travel much farther in a straight line due to the higher velocity and greater energy. For instance, a 9mm bullet fired from an MP5 submachine gun can travel up to 400 meters (1,312 feet) before it starts to drop significantly, while a 9mm bullet fired from an AR-15 rifle can travel up to 2,000 meters (6,562 feet) before it hits the ground.
It is important to note that firing a gun in a residential area or a public place is extremely dangerous and illegal. A bullet fired from a gun can penetrate walls, windows, and doors, and potentially injure or kill innocent people. Therefore, it is crucial to follow gun safety rules, store firearms securely, and never point a gun at anything or anyone unless you intend to use it in self-defense or for lawful purposes.
Additionally, it is important to be aware of the legal restrictions on firearms and ammunition in your jurisdiction. Depending on where you live, there may be laws that regulate the type of guns and bullets that you can own or carry, as well as the places where you can use them. It is your responsibility to educate yourself on the local gun laws and comply with them.
In conclusion, a 9mm bullet can travel up to 1,500 meters in a straight line when fired from a handgun or a submachine gun, and up to 2,000 meters when fired from a rifle. However, firing a gun in a residential area or a public place is dangerous and illegal, and it is crucial to follow gun safety rules and comply with the local gun laws.