Core Temp RC6 works on AMD APUs. If it doesn't work on Kaveri then you should report it to the author of Core Temp so it can be updated.
HWiNFO might also work. They have a list of AMD CPU/APUs listed on their website that their software works with and they update it frequently.
With Kaveri being new and far more complex than past processors you should expect programs and drivers to take some time to be updated as necessary. AMD has no control over what other companies provide for drivers or software.
Building a reliable PC involves more than just assembling the parts. You need to be able to configure all of the BIOS settings appropriately. This can be quite involved and frustrating as it can require a lot of trial and error with stress testing. It is however often the only means to get a 100% reliable PC.