Stir together the 7 minced garlic cloves, 1/4 cup olive oil, 1/4 cup lemon juice, 1 tablespoon salt, and 1 1/2 teaspoons pepper in a large bowl. Rub the marinade all over the lamb in a bowl, then truss tightly and marinate at least 3 hours in the refrigerator.
Preheat a grill for direct and indirect cooking over a medium-heat fire. Grill the lamb over direct heat until nicely charred, about 8 minutes per side, turning often. Then move to indirect heat, cover, and cook until the internal temperature reaches 125 degrees F for medium-rare, about 50 minutes, turning occasionally. Transfer the lamb to a cutting board and let rest 15 minutes.
Toss the asparagus with the 2 tablespoons olive oil, salt, and pepper. Grill the asparagus until tender, 6 to 8 minutes.
Pulse the remaining 2 whole garlic cloves in a food processor with the parsley, mint, the remaining 1/2 cup oil, the remaining 1/4 cup lemon juice, 1 teaspoon salt, and 1/2 teaspoon pepper.
Serve the lamb, sliced, with the asparagus and chimichurri sauce.