As others have said, yes, you can store your bags at the resort. We almost always arrive early, heck during split stays I've been known to arrive 7 or 8 am. Pre-Covid I always go to the front desk when I get there just to let them know I'm physically there. I never pick a certain type of room or a view, I really don't care, especially in a non-deluxe resort. I tell them I am o.k. with anything that is available. Sometimes I've been lucky and a room is actually ready and sometimes I will get the room ready text way earlier than "official" check in time. I also always put early check in as a priority on my on-line check in. After I have checked in, I head to a park. Depending on the time of year, some of the parks are open until 9, 10 or 11 so if I get there between 2 and 3, I still have lots of hours in the parks.
You don't say how far you are flying and what your party is made up of. If you have a long flight and littles, relaxing at the pool might be the best bet. If you have a shorter flight and little's you might be able to hit a park to let them let off some steam. If you are adults and, say kids over 9, again heading to a park might be a good bet. Depends on if you want to spend for that park ticket and if you can get a park reservation for a park you would want to go to. I'm going to say that if you have kids, DS might not be a good idea because, let's face it, it's shopping and food and walking. While kids love food, shopping is not always their favorite thing and they might be disappointed that they are so close yet so far away from a park or pool.