No he was not Somali. He never once refers to himself as Somali in Futuh Al Habash. Bar a few loyal leaders, the Somalis even plotted to abandon the campaign at one point after they had their fill of Booty.
Even though the influence of the Adal Sultanate extended to Somali territories East of Harar and Zaila, the nucleus of it was not Somali and most probably a Habasha Muslim led Sultanate. The Ethio-semitic speaking Harari people evince this. We owed allegiance to him just like the Afars and Harla.
Our position in the Sultanate is comparable to the Germanic tribes that lived in the Rhine frontier as subjects of the Roman Empire.
Knowing how unruly and fiercely independent we Somalis were, we probably disliked the authority of the Ifat/Adal Sultanate. We should have stabbed him in the back, taken Harar for ourselves and expanded to the heavenly Hadiya Bale mountains before the Bloody Oromos. All is fair in love and war.