The probability of a tie in baccarat is 0.095155968.
At the usual win of 8 to 1, the expected return to the player is 0.095156 × (8+1) - 1 = -0.143596.
At the a win of 9 to 1, the expected return to the player is 0.095156 × (9+1) - 1 = --0.048440.
The expected player loss is 0.143596/0.048440 = 2.9643960 times higher at a win of 8 to 1. Thus, the casino would need 2.9643960 times as much action on the Tie if they increased the win to 9 to 1 for the expected casino win to be the same.
This question is raised and discussed in my forum at Wizard of Vegas.