OP, have you considered a Crosstrek? They are cheaper and offer the same AWD system. Only difference is you’re getting slightly less cargo space. With used cars you never know how the PO treated them. CPO means nothing other than a warranty and a visual inspection. I have not heard too many good things about Subaru’s extended warranty plan. Mainly cost/coverage ratio. The longest plan runs about $4k if I remember right. $4k can pay for a lot of repairs on a Subaru. I say skip the warranty and get a new crosstrek, possibly even Impreza if it fits the budget. Service at the dealership if possible or find a good Indy. Skip all the dealer recommended stuff and only do what Subaru specifies. I paid for a valve cleaning at 30k and my outback never ran right again.
If a forester is a must I would still skip the warranty and give the car a good look over before purchasing.