before you offer $10000, consider that this ride blue books at $9570 in excellent condition. you dont want to start at your absolute highest bid (especially if it's more than the car is worth), cus he'll still try to get you to meet him in the middle. if you say no then he'll give you this "i'm not really in a big hurry to sell it" line and then you'll be considering paying considerably more than it's worth, or walking away.
i'd say offer straight blue-book, assuming that the car comes with complete current records. if not, deduct from there. bring up any and everything you can find wrong with the car to make your case as to why straight bluebook is fair for both of you. since it has an alarm you might give him about $100 headroom for it. just dont get suckered into buying this car no matter how much it costs, because he is not ineterested in giving you a good deal, as nice as he may seem.
BTW, edmunds.com gave an estimate of $9317 for this car in the best condition rating they have. this was based on my zip code, 97701 (bend, oregon, population about 60,000)