I would think that uninstalling perl with yum would not be a good idea, as there are many things that need perl but the version is not critical at all.
You might get several things removed that cause other problems.
I would probably try removing perl with a rpm --nodeps command (and perl-suid if you have it installed) ... then try manually installing new perl with rpm.
If there are any things that require 5.8.8 version of perl, they should complain on the install.
It would be better to test this method on a test machine first
Then, excluding perl in the centosplus repo would be good.