Does Yandex Support Schema Markup?

Short answer: Yes

Much like Google, Yandex does support schema markup/semantic data markup and uses the same Schema.org library.

How Yandex Uses Markup Data

Different schema mark-up can be used to highlight different things to Yandex; some of these being:

Does Schema Markup Give A Ranking Boost?

No.

Schema mark-up helps Yandex better understand page content and can lead to rich snippets within search results pages. But it does not offer a direct ranking boost.

This has been confirmed by Yandex.

Does Yandex Support All Schema Markup?

No.

The full list of what is supported can be found here.

How Long Does It Take For Rich Results To Show In SERPs?

If your schema implementation is valid, has been crawled (and indexed), and then has been moderated, it can take around ~2 weeks from this point for rich results to show in search results for relevant queries.

You can check the markup validation through the Yandex schema validation tool.

You can check the index status through your Yandex Webmaster Tools platform.