TLDR: Buy the Mi 9T, don't even wait for the Pro version. You won't miss anything on the Pro given your declared use-cases, all of those that you mentioned you can do on the 9T + more money for you because it's significantly cheaper.
Here are the things I noticed about the Mi 9T:
1. As we all know, the build and the cooling system of the Mi9T-series were spec'd to deal with SD855 high-performance SoC which is and certainly an overkill for the SD730.
2. As explained in #1, what you would get is significantly higher run-time for the performance cores + GPU on full load (max clocks) when you have a lower TDP SD730 SoC.
3. SD730 also sips power at full load and is overall having lower power consumption (then the Pro) which also converts to longer run time per single full charge.
Remember that you have a phone with passive cooling which could always be saturated especially during summer. The question is that for how long before saturation? Simple, SD730 would take longer time to saturate a cooling system designed for SD855, that's it. I always notice people getting disappointed gaming on a phone with SD845 (for example) and got mad because it could easily throttle at FULL LOAD, where is the liquid cooling? What the cooling system is doing? My answer would be: With great power comes faster passive-cooling saturation.
Forget Mi8, very small battery for gaming, lowest runtime of the 3.
Forget Poco, it's overkill for your use-cases (SoC-wise) and it's camera is dated and offers less utility as compared to the cameras of the Mi9T.
Buy the Mi9T, it's best for the price and the use-cases you have stated. I also has the overall highest battery run-time of the 3.
Oh, the Mi9T Pro? Forget it, just buy a Mi9T with the biggest storage space and call it a day.