Coach late in bringing team out for 2nd half

[RookieDude]

Had a couple of newer officials ask me how to handle this.

They had asked some other veteran officials in our association and had gotten different answers.

Situation:
Boys JV

Team A has delayed coming back on the court, from the locker room, to start the 2nd half.
Game management sent someone to the locker room to advise Coach A that he needs to get his team on the floor....still no team A.

Officials use the resumption of play procedure and put the ball on the floor...since the arrow was Team A's.
Violation...officials give ball to Team B for throw-in...Team B goes in for an uncontested lay-up.

Officials decide not to put ball on floor again and issue a T on Team A.
Coach is now coming back from locker room as Team B is shooting the 2 FT's for the T.
Coach A says nothing...and later says he is fine with the procedure used.

Did the officials use the correct procedure?
What would you have done if you were the R?

10-1-5a
10.1.9 COMMENT