Congrats on getting your first pair of CLs and an excellent choice!
About waitlists, it depends on which boutique you're dealing with but generally if you fill out a customer agreement form (which includes payment and shipping info) then you surpass others on the waitlist who have not filled out a form. This has usually worked for me in the past, just one time things fell through. Every boutique has a different policy about the customer agreement form. For some boutiques, filling out a form means that you have agreed to purchase the shoes but they will give you a courtesy call to let you know they've arrived at the boutique. Most boutiques though don't hold you to the customer agreement form if you decide in the end you don't want the shoes.