Adrien If a plugin does not add it's own tables to the database, that plugin will work by default. If a plugin creates its own tables, then they'll have to check it works with SQLite or change it however, once WordPress officially releases support for SQLite, I imagine developers of plugins will follow to make sure it works to deter people jumping ship of their plugin.
For example, Yoast SEO creates it's own tables within the database and I can say with 99.99% certainty that Yoast will support SQLite because the creator of Yoast is a contributor to the WordPress SQLite code.
I imagine full support to be released within 12-24 months however, as WordPress as already refactored code so it works with their own tables, technically, it's 'ready'.