An Ancient Chinese document from the 9th century referred to the northern Somali coast — which was then called "Berbera" by Arab geographers in reference to the region's "Berber" (Cushitic) inhabitants — as Po-pa-li. The first clear written reference of the sobriquet Somali, however, dates back to the 15th century. During the wars between the Sultanate of Ifat based at Zeila and the Solomonic Dynasty, the Abyssinian Emperor had one of his court officials compose a hymn celebrating a military victory over the Sultan of Ifat's eponymous troops.
Is there an answer to this question (If it cannot be answered, say "unanswerable"): What did the Arabs call the northern Somali coast in the 9th century?
Berbera