In a medium bowl, combine the shrimp with olive oil, Cajun seasoning, paprika, cayenne pepper, garlic powder, onion powder, salt, and pepper. Toss well to coat the shrimp evenly. Set aside to marinate for at least 15 minutes.

While the shrimp is marinating, rinse the rice under cold water until the water runs clear. In a medium saucepan, bring the chicken broth to a boil.

Add the rinsed rice to the boiling broth. Cover and reduce the heat to low. Cook for about 18-20 minutes, or until the rice is tender and the liquid is absorbed. Remove from heat and let it sit covered for an additional 5 minutes.

Fluff the rice with a fork and stir in the chopped parsley, thyme, and lemon juice. Set aside.

In a large skillet, heat a little more olive oil over medium-high heat. Add the marinated shrimp in a single layer and cook for about 2-3 minutes on each side, or until they are pink and cooked through.

Serve the spicy Cajun shrimp over a bed of herb rice, garnished with additional parsley and lemon wedges on the side.