Can you make a pass line bet after the shooter has established a point ?
Yes, you can but you shouldn't. You should make a come bet instead.
If the point is 4 or 10, then your probability of winning
would only be
3 / ( 3+6 ) = 1 / 3.
But a come bet would have the same probability
of winning as a "proper" pass line bet
( viz. 244 / 495
≈ 0.493 ).
If the point is 5 or 9, then your probability of winning would only be 0.40.
And if the point is 6 or 8, then your probability of winning would only be 5 / 11 ≈ 0.45