If you look at the rear corners, the clear coat has been "burnt" off & the base coat of the paint has been affected. When the clear coat is compromised like this, sanding it will only damage the base coat even more. The only option is to repaint the entire section, but you can't simply spray clear coat over it & call it good. If you were to do that, you would have a shiny surface covering the previously damaged clear coat. What this means is first the red base coat would need to be sprayed on the damaged areas...most likely the entire section would need to be covered & then some surrounding panels would need to be blended with red base coat. Then the entire area would be clear coated.
Theoretically this would be a simple job for a competent painter, but the issue is color match. Because this car is 11 years old, it's not as simple as going to the paint store, giving them the paint code of the car & having them mix the color. From the factory, paints have what they call "Variants", meaning if the color is called "Brilliant Red" (I'm making this up), there can likely be 12 versions of that color depending on the plant the car was built & the day the paint was mixed. One Toyota/Lexus color I made the mistake of using had almost 40 variants, which made color matching basically impossible without using some advanced techniques.
You are in a very lucky position, however. Since this area is on the roof, any color mismatch it's less likely to be noticed as opposed to many cars where the bumpers have been resprayed. What I would do is keep the repair contained to the borders of the affected spoiler panel. Find a shop where you can explain to the painter you only want him to touch up the areas where the clear has burnt away with fresh red base coat, & then clear coat the entire spoiler using the body gaps as his boundaries to tape off the rest of the car. When spraying clear coat, you need to cover the entire panel or you will get hard paint edges that will look very unsightly when the car is unmasked. Those edges are basically impossible to remove, which is why the entire panel must be clear coated.
Good news it's a simple repair for a competent painter, bad news red paint is the most expensive to mix & all body work is overpriced. With that said, you can probably have this done for less than $1500 at a shop. If you're willing to try this yourself, I can walk you through the steps I would take...not sure I would use the stuff in that link, but the process would be the same.