You're now running "5.6 with user-space bugfixes from the 5.9 patch level added".
The kernel is still at the 5.6 level, but system libraries and userspace programs are at the 5.9 level.
There does not seem to be an easy way to identify the "level" of a particular kernel package.
But this command might be helpful:
rpm -q --provides kernel-2.6.18-238.9.1.el5 | sed -ne 's/^.*_u\([0-9]*\)) =.*$/\1/p' |sort -n |tail -1
It will output either nothing (for e.g. RHEL 5.0) or a single number, which is the "level" of the examined kernel package.
Technically, "rpm -q --provides" outputs all the "provides" keywords in the kernel RPM metadata, which include a lot of keywords of forms
kernel(rhel5_<some-kernel-subsystem>_ga)
or
kernel(rhel5_<some-kernel-subsystem>_uN)
where _uN indicates that the particular subsystem of the kernel is at least on update level N.
You cannot just look for a particular subsystem keyword, since not all subsystems receive new keywords at every level upgrade. For example, in the RHEL 5.10 kernel includes the following MD driver related keywords:
- kernel(rhel5_drivers_md_ga)
- kernel(rhel5_drivers_md_u4)
- kernel(rhel5_drivers_md_u7)
To find the "level" of a particular kernel package, you find the highest _uN suffix on all these keywords.
(Obviously, if you're only interested in just verifying that a particular feature that was added in a specific update level is present, you can just test for the presence of that particular keyword).