Hands up, don't shoot criminals

In a recent case, police were called to a downtown Orlando nightclub because of a report of a man brandishing a firearm. The surveillance video is found here.

A man was thrown out of a nightclub for fighting (:19). He pulled a pistol out of his waistband (:31), drops it on the ground, and waits outside of the locked nightclub with the pistol in a low ready position. He sticks the handgun back into his waistband at :58 and continues to pace outside of the club.

 The police officers (2 of them) confront the armed man at 1:40 with guns drawn. He does not obey commands to raise his hands. More officers arrive They shoot him with a Taser at about 1:55, at which time both of his hands go to his waistband. Most of the cops retreat, and the one center screen fires 9 shots. Seven of them hit the suspect, and one travels through the door of the nightclub and strikes a female bystander in the head, killing her. The suspect, who lived, is charged with murder for her death.

The local press does a story, and this is where the main point of this post comes in:

There is one commenter who has made the following statements
 
Another case of excessive force by Police. My prayers for Mr. Roach's full recovery.

First of all - Mr. Roach's gun was not loaded. Secondly - he had been tasered by the Police and his arm movements were caused by the electric shock - NOT because he was reaching for his unloaded gun.
This was an attempted assassination. And 9 shots? really?

Mr. Roach was isolated (had no hostages or cover) and was standing 5 feet away from the Police Officers.
Given these conditions - 9 shots from a 40 S&W is a ridiculous case of excessive force. A Police Officer is responsible for every bullet he fires. Spraying 9 rounds in a crowded downtown area is reckless.
Also, Mr. Roach had already been tasered by another Officer and was convulsing from the electric shock - he was not reaching for his unloaded gun.

My questions, which he won't answer:

1 When is it appropriate for a person to use lethal force?
2 How can you tell if a gun is unloaded simply by looking at it?
3 How many times can you shoot someone?