In the bowl of an electric mixer, combine the water, yeast and sugar; stir to dissolve the sugar and yeast. Allow the yeast to bloom in the bowl, forming bubbles or a foam on the surface of the water. Add the flour, 1 1/2 teaspoons of the salt and 3 tablespoons of the olive oil to the bowl and mount onto the mixer. Use a dough hook attachment to mix the flour and liquid on low speed until a dough is formed. Once the dough is formed, raise the speed to medium and beat the dough for 8 to 10 minutes. Remove the dough from the bowl and place in a lightly greased bowl covered with a damp kitchen towel (or plastic wrap), to proof until doubled in size, about 2 hours.
While the dough is proofing, heat 2 tablespoons of the olive oil in a 10-inch saute pan and once hot, add the fennel, 1/2 teaspoon salt and the pepper to the pan and saute until lightly caramelized, about 3 minutes. Remove the fennel from the pan and set aside until ready to use.
Preheat the oven to 450 degrees F.
Punch the dough down and place on a lightly oiled 9 1/2 by 13-inch sheet pan. Cover with a damp kitchen towel or plastic wrap and allow to double in size again, about 30 to 45 minutes. Use your hands to flatten the dough so that it fits across the entire pan. Spread the sauteed fennel across the surface of the dough, followed by the olives, pecorino, and rosemary. Drizzle the remaining 6 tablespoons of the olive oil over top the dough and place in the hot oven. Bake until golden brown, about 15 to 17 minutes. Rotate the focaccia halfway through the cook time to ensure even browning.
Remove from the oven and allow to cool for at least 15 minutes before cutting and serving.