How do I search for doc on App search with curl or kibana devtools?

I have created an engine on App search and there I have index some documents.
I can't access those index with my elastic search port like http://localhost:9200/index/_search

My question is how can I access those indexes from my elastic search port (localhost:9200) not app search port (localhost:3002)?

If I can access those form my elastic search port then I can use the Kibana dev tool console.

You should use App Search API and not elasticsearch API.