If you have a single node setup then you do not benefit from replicas. However, the cluster being Yellow will not prevent Kibana showing you documents from the index.
If having cluster status Green makes you happier then use a template. Something like
PUT _template/default0replicas
{
"template" : "*",
"settings" : {"number_of_replicas" : 0 }
}
But that will not determine whether documents show up in Kibana.