The Homepage Excerpts plugin can be used to reduce duplicate content while keeping full posts on the homepage. Suppose you have 8 full posts on the homepage. Once you activate the plugin you will have the option to select how many posts to display fully in the homepage. The options will go from 1 up to 8. If you select 8, all your posts on the homepage will keep being displayed fully while all the other posts (the ones on page two, three, four and so on) will turn into excerpts.

Remember that new pages usually take one week or more to get indexed by search engines, so that by the time your single post page gets indexed the post will already be out of the homepage, and it will be displayed as an excerpt, removing the duplicate content issue.

Apart from SEO benefits this change might also improve the user experience. Displaying only post excerpts on the subsequent pages will make it easier for readers to scan them quickly while searching for the post that they are looking for.