I don’t know about the right way, but I may have a bad one for you. (not tested)
Create a new directory within your content. (you’ve got a new section)
Add a _index.md in it so you can assign it a title, a url and most importantly your custom, layout.
Then test your current code as is. Your custom layout being on a list template, the .Paginate object may be available to you. That is if .Paginate is even designed to work with .Site.Data.Pages.
If it works, you can take a shower cuz this is dirty. If it doesn’t that’s probably for the best.
Thanks guys, I got it to work by creating the section.
For everyone else finding this posts, here is the final snippet of code
{{ range (.Paginate (where .Site.Pages.ByPublishDate.Reverse ".Params.unlisted" "!=" true) 9).Pages }}
{{ .Render "summary"}}
{{ end }}
Keep in mind I am using a .Params.unlisted that is specific to my frontmatter and use-case. Also, there has to be at least a _index.md file in the new section for this to work.