Sorghum: Combine sorghum and water in a large pot. Bring to a boil, then reduce to a simmer. Cover and cook for 45 to 60 minutes, until water is absorbed, then fluff sorghum with a fork.
Roasted Vegetables: Preheat oven to 450°F (232°C). Peel and cut carrots into ¼ inch (½ cm) coins. Trim and halve the Brussels sprouts. Peel and cut onion into large chunks. Zest the lemon (reserve zest for later), then cut the lemon in half. Place veggies, lemon, and thyme sprigs onto a baking sheet and drizzle with oil, salt, and pepper. Toss to coat everything. Bake for 25 minutes, or until veggies are soft and golden at the edges. Discard thyme sprigs.
Dressing: Squeeze the lemon juice from the roasted lemons into a bowl. Stir in 3 Tbsp olive oil, half of the feta, and season with salt and pepper. Stir about a third of the dressing into the cooked sorghum.
Assemble: In a large bowl, toss together roasted vegetables, reserved lemon zest, remaining dressing, cherries, and almonds. Spoon cooked sorghum into serving bowls, topping with roasted vegetable mixture.