I'm not aware of any Cisco native integrations or even any plans for any integrations. Very long term I might expect unified hardware, but the focus is on switches right now and enhancements to wireless.
However for your specific problem, you are likely seeing the access point IP instead of the client because the SSID in question is using NAT Mode. You could change that to drop to a VLAN the Firepower can see natively to get the reporting you want.