Compared to other contracts, the package is very low. Make no mistake about it, they could have offered this to a contract agency but they know there would have been no takers.
Other CRJ contracts pay about $9000 base (for a CRJ 200), more vacation days, more housing, a relocation allowance, and most of your international school tuition for your children. International school alone will run you around $20,000 per child per year.
Contract flying is the last hope in the airline world of making a decent salary. And the ASA terms and the pilots coming are helping to destroy it.
And don't forget, you are going to work in a communist country and won't enjoy the protections that you are use to. Unions? Forget about it. Min rest? You bet. Is management, operations and scheduling run by locals or ASA? That is going to make a big difference. What about if you have an incident or accident? Even in Japan, there have been pilots put in jail because of an accident. I don't work in Vietnam so I don't know what their legal system is like, but it is something to consider.
I'm not saying that you should be scared off from it. Since leaving the US 3 years ago to join the contract world, this has been the best move I have ever made, both personally and professionally. And I have NO plans of returning to the US. But your salary should reflect the risks that you are taking, and in its current form it does not.
Your contract for a 900 should be close to 737 or A320 contracts, not US regional pay.