When to call the Technical
 

A1 fouls out of the game. The proper order was done and a substitute checks into the game. Play resumes and I notice the player that just fouled out leaves the bench and heads to the locker room. But the resumption of play was with the opposing team with the ball and trying to score. I decided to delay until the opposing team had their opportunity to score. After successful shot, I blew the whistle and called the T. My question is would you have waited or called it immediately?

You handled it correctly. You dont want to put a team at a disadvantage for a violation committed by their opposition.

I wouldn't have called it at all. All A1 did was leave the bench? Did he demonstrate disgust on his way to the locker room?

The way you described it, there's no way this is a T.

In A Cup Instead ???
 

A technical foul for going to the men's room? That's rather harsh, don't you think?

Did you charge this T to the player? Because then not only do I strongly disagree with giving a T at all in this instance, but you misapplied the rule as well.

NFHS 10-5-5: “The head coach shall not permit team members to leave the bench area and/or playing court for an unauthorized reason.”

This is the only rule reference that justifies a T here, and if you're going to go there, you have to charge it to the head coach. Or you can just not go there at all...going to the locker room is an authorized reason to leave the bench.

Player ???
 

... he's not a player, he's bench personnel. He was disqualified with five fouls.

To add to the other comments: Before handing out the technical did you know whether the HC told the player to go to the locker room or whether the player asked and was given permission by his HC?

Sometimes it's better to leave well enough alone.

Leaving that one alone short of an overt show of unsportsmanlike behavior.

Not a tech unless done in an unsporting manner. Just like I'm not gonna call a tech for a kid changing his jersey in the bench area due to blood. Not the purpose of the rule.

Reasons ...
 

AremRed: I fully agree with you in practice, but in theory, be careful to differentiate between a player technical foul for unsporting and a head coach technical foul for unauthorized leaving the bench area. These two rules are not 100% interchangeable. Note the slightly different wording for the reasons to charge a technical foul, and remember a player is one of five, most others are bench personnel (head coach responsible), certainly a team member who has been disqualified with five fouls.

10-5-5: The head coach shall not permit team members to leave the bench area and/or playing court for an unauthorized reason.

10-3-6-I: A player shall not: Commit an unsporting foul. This includes, but is not limited to, acts or conduct such as: Leave the playing court for an unauthorized reason to demonstrate resentment, disgust or intimidation.

The rule below might be useful in regard to unsporting behavior as described in the original post (if a technical foul is to be charged, a separate question):

10-4-1: Bench personnel, including the head coach, shall not: Commit an unsporting foul. This includes, but is not limited to, acts or conduct such as: e. Objecting to an official’s decision by rising from the bench or using gestures; f. Inciting undesirable crowd reactions.

Yes, correct.

This is just me...I wait until B has finished their possession and A is in team control. Then I stop the game and make the head coach aware that he has a player that has left the bench and ask if he is aware. Second, I'd ask if an assistant has accompanied him.

If he's alone, I'd say something akin to 'for his safety, we need him back out here. I'm sure you understand.'

If I were the coach, id look at you like you were from Mars and say…"Safety? He's 17 years old…." If you are going to do something i'd say get him back out here...the rule requires he stay.

Now, if he is just heading to the locker room (not acting like an idiot) I'm not getting involved, at all. I don't care if he asked his coach for permission or not.

I would echo this entire post. That coach is going to make a big deal about you saying that. Why make a mountain out of a molehill?

I would not do any of this, nor would I recommend this to anyone. The OP, from what was described, was incorrect in.

1) giving the T
2) giving the T to the wrong individual

Unless its a sportsmanship issue the bench and what goes on there really isn't my concern. For all I know the kid needs to go p.p.

Overall a bad T and incorrect application of the rules. Learn from it and don't do it again.