The Catholic Encyclopedia has an article on Pope Boniface, that would at least help establish some of the basic facts before throwing out false assertions, such as that this is from the 9th century. This is Pope St. Boniface I, who is from the time of St. Augustine.
>Elected 28 December, 418; d. at Rome, 4 September, 422. Little is known of his life antecedent to his election. The "Liber Pontificalis" calls him a Roman, and the son of the presbyter Jocundus. He is believed to have been ordained by Pope Damasus I (366-384) and to have served as representative of Innocent I at Constantinople (c. 405).
And the part relevant to OP's quotation.
>In the East he zealously maintained his jurisdiction over the ecclesiastical provinces of Illyricurn, of which the Patriarch of Constantinople was trying to secure control on account of their becoming a part of the Eastern empire. The Bishop of Thessalonica had been constituted papal vicar in this territory, exercising jurisdiction over the metropolitansand bishops. By letters to Rufus, the contemporary incumbent of the see, Boniface watched closely over the interests of the Illyrian church and insisted on obedience to Rome. In 421 dissatisfaction expressed by certain malcontents among the bishops, on account of the pope's refusal to confirm the election of Perigines as Bishop of Corinth unless the candidate was recognized by Rufus, served as a pretext for the young emperor Theodosius II to grant the ecclesiastical dominion of Illyricurn to the Patriarch of Constantinople (14 July, 421). Boniface remonstrated with Honorius against the violation of the rights of his see, and prevailed upon him to urge Theodosius to rescind his enactment. The law was not enforced, but it remained in the Theodosian (439) and Justinian (534) codes and caused much trouble for succeeding popes. By a letter of 11 March, 422, Boniface forbade the consecration in Illyricum of any bishop whom Rufus would not recognize.
http://www.newadvent.org/cathen/02658a.htm