I know that i9 series was created based on Xeon chips but will iMac Pro use i9 series based xeon CPU? You know that i9 series have serious malfunctions with power consumption and heat. Will Apple use those CPU for iMac Pro?
We can only assume at the moment, but that assumption is that the iMac Pro will use as yet unannounced LGA 2066 socket Xeon CPUs based on the i9 Skylake-X core and x299 chipset. While they will be based on the i9, they'll likely run at lower clock-speeds and will be "top bin" models, which together should ensure their reliability and longevity.
We can only assume at the moment, but that assumption is that the iMac Pro will use as yet unannounced LGA 2066 socket Xeon CPUs based on the i9 Skylake-X core and x299 chipset. While they will be based on the i9, they'll likely run at lower clock-speeds and will be "top bin" models, which together should ensure their reliability and longevity.
Are you talking about the i9 thermal problems when overclocking it on Windows? Xeon cannot generally be overclocked, and certainly not on macOS on Apple hardware.
Early speculation was that the Intel C422 chipset would be for LGA 1151 (so quad-core Xeon E3 CPUs), but Gigabyte released an LGA 2066 workstation motherboard with that chipset that supports i9 CPUs and the Gold series Xeon equivalents. So I am guessing this will be the iMac Pro's chipset.