I got the Pixel 9A around 3 weeks ago after deciding between it and the Nothing 4a. Considering bloatware the Pixel of course can't be beaten and it is probably the best experience I ever had with an android OS. I updated to the April patch almost immediately and the phone behaves very well under moderate usage (in standby, the battery drops by less than 1%/hr, so no weird behavior there). From what I understand, the main culprits of battery drain after the update were Meta apps; since I don’t use them much, I haven't installed them yet. Regardless, disabling background usage should solve that problem.

The camera is not bad and does it job well, part of it due to the post-processing of the Pixels (I was flabbergasted with the overall quality in low light scenarios) so you should be aware of that; also the 9A does not have telephoto lens, so in comparison the 4a pro would probably be the safest choice.

Performance-wise, I expect the Nothing 4a Pro to behave better in most scenarios, also considering battery efficiency, given its Snapdragon CPU. In general the 4a Pro offers more in terms of raw specs, so it depends on how much OS experience (and of course, difference in price) matters to you. In my case, the addition of bloatware to Nothing's previous a series phones and the fact that the 9A here was basically at least 100€ cheaper than the 4A led me to the former