I have a reservation, but will be arriving after 9pm to the campground. Could arriving late be a problem?

No problem. You can check next morning

Nope. Be sure to check in the next morning and get your site window sticker. It lets you use the boat launch and day use area without a discovery pass.

As long as you can manuver in the dark,you should be just fine.

Nope u fine if u have a reservation don't worry