his will be my first time to the UK, and I will be there for 9 days to visit my husband. We are going to be applying for my spouse visa this summer...but first I am going there to visit. So, being from the US, I do not need a visitor's visa right? And our infant son was born here in the US and only has his US passport for now. .. I am sending for his UK one on Monday.. But will he be alright using his US passport for now to enter and come back on?
No, you do not need to apply for a visitor visa for a visit of only a few days - you will be given a visitor visa stamp at the airport when you arrive.
The only reason at this stage you might need to apply for one before you travel is if you believe there is a significant reason why you might be refused entry to the UK at the border... for example, if you have criminal convictions, you have previously tried to enter the UK and have been refused in the past, or have applied for a UK visa before and it has been refused etc.
As you are visiting a close family member though, I would be prepared to show you are just visiting at this stage and that you aren't trying to move to the UK without a spousal visa. It's a good idea to show that you know the visa rules, that this is just a short visit and that you will be applying for a spousal visa soon. Also, you should have your return ticket and evidence of your home and life to go back to in the US after your visit.
Your son should ideally enter the UK on his UK passport, as he is a UK citizen and that will be his proof that he is entitled to enter as a citizen, but if the visit is only for a few days, then there shouldn't be a problem with him entering on the US passport for now - it's just that he will be admitted as a US citizen on a visitor visa and so will be restricted to visitor visa rules.
Also, I am a Stay-At-Home-Mom, and my husband provides for us. What do I need to bring as far as something to show I have money to travel on and such?
As you are only staying for 9 days, it won't be too much of a concern as they won't be expecting you to have large funds to be able to support yourself.
But if you don't have much money in your bank account to show them, then you can have your husband write a letter of support for you and he will need to give you his original bank statements and payslips to show that he has enough money to support you for your visit.
