with IDM, if you are after IP-MAC binding without an IP address on the vlan interface [e.g. without leveraging the ARP table of the switch], enabling DHCP snooping [part of IP security] should do the trick.
The following table in the 21.1 userguide [Table 86: Identity (User/Device) Attributes and Source Software Components] provides which features can be leveraged to get specific information.
note that you can be in 15.x and still leverage DHCP snooping to get the IP-MAC binding.
Having an IP interface on the vlan should not be necessary.