The simplest, and probably the correct, way to configure php-fpm with apache in Centos 6/7 is by using SetHandler and ProxySet directives.
The snippet bellow show a simple Virtual Host example, just change lines 2 3 and 6 and you are good to go.
<VirtualHost *:80>
ServerAdmin [email protected]
Servername example.com
Options +Indexes
DirectoryIndex index.php
DocumentRoot /var/www/html
# Register php-fpm as the handler for (.*).php files.
<FilesMatch \.php$>
SetHandler "proxy:fcgi://localhost:9000"
</FilesMatch>
# Configure the proxy
<Proxy fcgi://localhost:9000>
ProxySet connectiontimeout=5 timeout=240
</Proxy>
# If the php file doesn't exist, disable the proxy handler
# so we can gracefully fail.
RewriteCond %{REQUEST_FILENAME} \.php$
RewriteCond %{DOCUMENT_ROOT}/%{REQUEST_URI} !-f
RewriteRule (.*) - [H=text/html]
</VirtualHost>
After saving and restarting/reloading your apache server, you now have a fully functional php installation.
The advantage of this method is that it selectively send requests to your php-fpm server and you gotta keep .htaccess compatibility.
Sources:
https://httpd.apache.org/docs/2.4/handler.html
https://httpd.apache.org/docs/current/mod/mod_proxy.html