Hi,
One thing to note here would be, which protocol are you using for discovery and inventory of the iDRAC. If you are using SNMP or IPMI you will not get the software inventory table populated. For the inventory table to be populated for the 9G and 10G servers you will need to discover and inventory the server, and not the RAC, with OMSA installed on them using SNMP or WMI protocols. If it is an ESXi, then choose WSMAN protocol.
If you have iDRAC6 and iDRAC7 in your environment you can manage them using WSMAN protocol and that will fetch you the software inventory table.
Once the software inventory table is populated for the devices you will be able to see them using Repository manager.
If both your servers and the iDRAC are in different subnets, you will need your OME server to be connected to both the subnets so that all the servers can be discovered.