I am still using Oreo blobs (because Pie wasn't released when I started working on the Pie bringup) and you should have the latest Stock Oreo on your device.
I don't know how many more times I need to say it that you need to stay away from SODP and their kernel and ESPECIALLY their OEM binary.
I understand about staying away from SODP kernel and OEM binary, which reminded me of the time when I tried to build AOSP according to the "official guide" and flashed the images (including OEM) into my device only to find out the result was a total nightmare that would throw tons of errors (bluetooth-related and some others) then power itself off after a few seconds, what a disappointment.
Currently I do have recent stock Oreo blobs on my device, yet the generated cr-7.0 ROM zip could not boot after flashing from TWRP. The AOSP fiasco forced me to flash the entire stock Oreo ROM with FlashTool before flashing CarbonROM as the SODP OEM binaries broke the phone call functionality (I could not hear the other side, nor could the other side hear me, a total silence).
As for the question about whether recent stock blobs (from Pie) would be needed was mainly about the changes on stock Pie that people have already noticed, notably the camera, which no longer saves green photos compared to stock Oreo, on an unlocked device, although that alone might not be enough.
This is by far not enough. The camera quality will likely decrease (it always did) so the drm fix is still recommended. What Sony did is avoiding a long overdue lawsuit due to literally breaking users devices.
Isn't it interesting how the update to fix camera issues that existed since the X Performance that was released over TWO year ago has been fixed less then two weeks after class action law suites were made legal in Europe, Sonys main market?
The mere fact, that they PROVED they could fix it throws a big ball of shade on the whole company. You can't tell me it took them 2 years to fix (especially as I know how the DRM fix on XDA works) so they clearly just didn't care at all before.
This is far from being anything near developer friendly. This is a ****show.
Still, It's possible that a 4.9-based stock kernel would be needed to get a bootable build for cr-7.0 (I once asked in the thread regarding the stock Pie firmware and the answer was 4.9).
For now, the 4.9 stock kernel in question (along with recent stock firmware builds) is not yet on the kernel copyleft archives. But anyway, I've got an overall understanding of the current status of cr-7.0 for our device, and I'll be looking forward to an official release in the future.