To buy or not to buy

1) no

2) you can't

3) you have to assume that the battery only has a few more years, and plan on that as part of your purchase.
if it goes longer, you're ahead of the game.
if shorter, you at least have a plan.

 

If you have Techstream running on a Laptop with a Mini-VCI cable you can read the voltages for every 2 modules in the HV battery pack. If one of these 14 readings differs significantly from the others, it's indicative of an imminent failure (each battery module is ideally exactly the same as all others for all battery states of charge). Need to have a decent understanding of batteries and working on cars to do this. Otherwise there's not much you can do. Google and search on PC the terms in my post if interested.

 

Simplest way to find out is buy an OBD2 reader via this buying guide: Hybrid battery diagnostic and repair tool for Toyota and Lexus Then install Dr. Prius App and they have a series of tests you can put vehicle thru to measure battery health. If I bought 88K mile 2009 I'd be super excited, 'because Prius newer than that are so incredibly ugly... But I would want to get battery charged up and balanced, eventually conditioned to ensure many more years of life. You can learn about that here: hybridautomotive.com/pages/faq

Also don't listen to the rich weirdos on here that say all old Prius should be thrown away, they're waste and gluttony personified. Also very cruel and indignant towards people who have no interest in wasting a ton of money on a car...