Thanks to everyone for your prompt and insightful input.
Seller needs funds to buy another property to move into, that's why they can only vacant property after closing day. I don't really have a choice here because I'm in Los Angeles County where seller usually has more privilege than buyer.
Also, property is sold as is, so it makes no difference if I find mold or damaged walls when vacant that were covered by furniture on closing day.
I took everyone's advice and asked agent to add below clauses:
1. $10k to be held by escrow until property is vacant to cover possible eviction, cleaning or damages caused by moving;
2. Seller is responsible for taxes, insurance & utilities until property is vacant;
3. Seller shall pay $200/day after 3rd day of closing if property is not vacant by then;
4. After 10th day, eviction will be filed if property is not vacant by then.
I hope I didn't miss anything. Again, thank you all very much for your kind help.