If I buy tickets that day can I use that money at the ens of the day towards a yearly pass have never been there dont know if he would like it enough to go back a few times through the year thank you

Usually yes

Not sure, call and ask

I would guess so, but check at the front desk first. You can also use your yearly pass for entrance to a lot of other science museums around the country (or discounts in a few cases)

I did on my family's recent visit. Note that passes for the special shows (bubbleology or whatever) are separate.