Official media said they all belonged to an Islamist guerilla cell and had conspired to kill a Moroccan wood merchant in Casablanca as he was closing his shop on 11 September last year.
Police investigations insist the nine belonged to the Salafist Jihad, a group blamed for carrying out the coordinated bombing attacks in Casablanca on 16 May, that killed 45 people.
A court in the capital Rabat on Friday handed down a 20-year sentence to ex-policeman Khalid Adib for his involvement in the killing.
He was accused of leading a cell plotting to attack Jewish interests in Morocco.
Four others of the same cell were jailed for 15 years, one for 10 years, two for five years and one for two years.
A lawyer of one of the suspects said the charges against all those prosecuted had been "made up."
"Authorities needed scapegoats to restore calm among the Jewish community. Some of those sentenced were Islamists, yes. But they had no link with the killing," the lawyer said.
The wood merchant's killing was followed the next day by the stabbing to death of a Jew in the northern city of Meknes.