I’ve noticed that, in addition to appearing at the top on my homepage where I want it, my sticky post appears on my second page of blog posts, in accordance with when it was originally written. Is there any way with CSS to take it out of the flow of dated posts and only have it appear at the top of my homepage?
No. It will always be in the flow of posts. It it were before the fold (on the main page) it would not show up except in the sticky location, but once it gets bumped to the 2nd page, then it will show up.