By hook or crook u have to convince your sister to sign in order to sell it off. Any one of the owner on the land title refuse to sign, the deal will fall off. Happened to one of my grandfather's land in the past and still hanging till now.

Another method if your sister refuse to sell, just do land division/pecah tanah on the 8.95 acres and apportion according to the share. After land division then each of the owner settle on their own. This process will incurred some fee but it will be trouble-less for each owner in future.

Mind to suggest how to solve the deadlock situation if TS sister refuse to sell?

If she give reason like  “tanah pusaka” , I don’t think money is going to convince her. Unless you offer like ridiculous amount that TS wouldn’t have the resources to.

Best approach is let her take over the administration of the land. Handling all the payment of quit rent and what not and later got squatters etc let her handle it , once women get a taste of the troubles normally they fold.