Well first, don't let appearances fool you. Looks clean isn't the same as clean. OK, now on to its worthiness. $9800? NO. Maybe 7 at the most, 7500 if they really don't wanna go any lower. 6 is a great offer and I've seen better sell for less. Have they done the 90k service yet? If not, thats a huge bargaining chip. Service and parts, you're looking @ ~1500. What about the condition of the usual wear and tear items (struts, shocks, brakes, tires, etc)? What's the condition of the fluids? ALL the fluids (especially PS and tranny) save for the rear differential since that one is not easy to check. Reason to check PS fluid is if it looks bad, they probably haven't kept up with changing it out and the seals may be ready to leak.... all over your alternator. Don't know the exact amount on that replacement with labor but have read it's a pretty penny.
I'm also not aware of the usual breakdown items on the 1st gens but I'm sure some one else can chime in on that. Since there aren't many service records available, a good alternative would be to ask the seller to let the car get PPI'd at a Lexus dealer or really any superb mechanic. Browse the forums, do searches, there is an incredible wealth of knowledge here that can provide you with even more bargaining chips.
If everything checks out, then haggle and buy. If they really don't wanna sell for what you're willing to pay for, find another one (there are more out there, trust me). These are great cars provided that regular maintenance is performed and will last several hundred thousand miles easily if taken care of.
Oh and one last thing. If you do end up passing on this car, read this: http://www.lexls.com/info/lsgenerations.html
It ought to help you find the exact year/gen LS you want.
One last last thing. Welcome to CL.