I recently got myself a Pixel 9 Pro XL because I needed the larger storage, I use it offline alot so I have alot of things stored there.
The camera's are indeed fantastic, and I could not think myself without the periscope telelens anymore.
Also, the slightly larger screen is better for my eyes.
The larger RAM is great for my offline AI usage. (I use ChatterUI)
I did not regret my purchase, I love my XL.
However, the Pixel 9a has a slightly greater batterylife, and if you use screenprotectors, the ultrasonic sensor might not be ideal, (at least in my experience, I think its best to do some research on it first) then the Pixel 9a might be the better option.
I wouldn't worry about the large bezel on the 9a, after applying a case I suspect it will become less aparent.
Also, you save quite a buck with the Pixel 9a.
In short; if you buy it for the camera and the larger screen and big storage and don't mind spending the extra cash, go for the XL, but if you want a a slightly smaller phone, (more pocketable) better batterylife and save a whole lot of money, go for the 9a.
I honestly don't think there is too much difference between them though, apart from the camera's, however, I do not own the 9a, so I'm not sure.
I would suggest to compare the specs, and see what fits best for you:
https://m.gsmarena.com/compare.php3?idPhone1=13478&idPhone2=13217