Just reviewed the release notes and did not found new information about new IPv6 features.
Since software release 8.11 the firmware include IPv6 support for the management interface to use http(s), ssh and SNMP with a static IPv6 address. IPv6 for wireless clients is only support in briged@ap mode and requires services like SLACC or DHCPv6 on the wire side. I think policy (roles) support and IPv6 address in the client reports are still missing, but haven't tried it.
V9.0 seems also to support IPv6 adresses for NTP, Syslog, DNS, RADIUS, SCP and FTP servers (comments in user guide).
Some information whats on the IPv6 roadmap would be great.