Mullet Bay questions

We visited Mullet Bay once several years back, before they had the umbrellas there, and loved it. I can't remember how much time we needed to allot for traffic back to the cruise ship, but knew we needed quite a bit. I see that it is more popular now than it was then and wondered how early we need to be there to get an umbrella and chairs? Our ship is one of two in port that day and doesn't get in until 10 am and leaves at 6 pm. What time would we need to leave Mullet Bay to get back to the port with time to spare?

Also, how good are the chances that our cab will come back to get us if we ask them to??? This is important to me because I cannot walk far.

Thanks for any advice!!