Hi 
I’m looking on the marketplace for v9 compatible themes, but I can’t find any.
No theme has been updated to v9.
Do you know if it is possible to find it on another site ?
Replica Pro is V9 ready.
Searching the marketplace for “version 9” only hits 3 themes
https://marketplace.concretecms.com/marketplace/themes/-/view/?submit_search=1&search_keywords=version+9
Two of them are mine and are very special purpose, not suited to general site themes. As well as Modena (listed in the above search), as @cmerritt notes, Replica Pro has been updated for v9, but is not listed.
Thank you all for your responses and help.
I hope that new v9 compatible themes will arrive very soon.
Honestly I find that concretecms is one of the best and very easy to use. I like it.