The bus driver was later assaulted, although the 14-year-old was not involved in that attack.
The court heard the boy did not have racial prejudices but had instead just “joined in” the violence.
Judge McCormack said she accepted he had made a “stupid mistake” and was sorry for his actions.
The boy’s mother, who was in court, was ordered to pay £150 compensation to the bus driver.
Later at the same court, another boy who was arrested on his 13th birthday for taking part in the same riot has been sentenced.
The teenager was given a 12-month referral order for throwing objects – including an egg – at police.
Judge McCormack told the boy he and others outside the Holiday Inn had been “terrorising people trying to go about their daily lives”.
“You may have been 12 but you knew what you were doing was wrong,” she told him.
