The restart is a direct free kick for the opponents or a penalty kick if the recipient was inside of his own penalty area. It is also a send off for the player who spit.
Charging an opponent is a direct free kick offense.
because spitting is descusting
A free kick. Depending on the category of the foul, it can be either a direct or an indirect free kick. The difference between the two is that a goal can be scored from a direct free kick (but only against the opponent) whereas a goal cannot be scored from an indirect free kick.
There are seven offenses that result in a direct free kick if done in a manner the referee believes was careless, reckless, or using excessive force: kicking or attempting to kick an opponent tripping or attempting to trip an opponent jumping at an opponent charging an opponent striking or attempting to strike an opponent pushing an opponent tackling an opponent There are three more offenses that result in a direct free kick if any player does them, regardless of carelessness, etc.: holding an opponent spitting at an opponent handling the ball deliberately (except the goalkeeper in his or her own penalty area)
An indirect free kick is when the kick is unintentional.
It is neither direct nor indirect. That said, a goal cannot be scored directly from a throw-in. The restart would be the same as if the score was directly from an indirect free kick. If the ball enters the opponent's goal then it's a goal kick for the opponents. If the ball enters the thrower's goal, then it's a corner kick for the opponents.
Spitting any any other person is, as you say, an send off offense. If the spitting is directed at an opponent, a Direct Free Kick is awarded to the opposing team at the spot of the infraction. As a result, this would become a penalty kick if it happened in the opposing team's penalty area.
A direct free kick.
in order to score a goal, an indirect free kick must touch another player before entering the net. A direct free kick does not.
It will be a indirect free kick.
An indirect free kick must be touched by another player before it goes into the net to count as a goal. A direct free kick does not.
A kick-off is neither a direct free kick nor an indirect free kick. Kick-off, DFK, and IFK are three different and distinct restarts in the list of 8 possible game restarts. Your question appears to ask, "can you score on a kick off?" The answer is yes, but only against your opponent. You cannot score an own-goal on a kick off.