Preheat your oven to 375°F (190°C). Line a baking sheet with parchment paper or lightly grease it with cooking spray.
Slice each jalapeño in half lengthwise and remove the seeds and membranes for less heat, if desired.
In a mixing bowl, combine the chopped shrimp, cream cheese, shredded cheddar cheese, green onions, Cajun seasoning, garlic powder, salt, and black pepper. Mix until well combined.
Spoon the shrimp mixture into each jalapeño half, filling them generously. If using breadcrumbs, sprinkle them on top for added crunch.
Place the stuffed jalapeños on the prepared baking sheet. Lightly spray or drizzle with olive oil.
Bake in the preheated oven for 20-25 minutes, or until the jalapeños are tender and the tops are golden brown.
Remove from the oven and let cool for a few minutes before serving.