How many days? I think it depends on what you want to do and what you want to spend. If you just want to go to SW and see a few shows, pet the dolphins, ride the rides, it can be done in a day. And it will be a fun day!
If you want to do special dinners or tours and still do all the rest of the park, taking time to actually read, listen, and learn while you are there it can take 2 days or more. This of course also depends on the days you go. Is it during winter when park closes early or during the summer when the park is open till 9 or 10? Is it a holiday, a weekend, or a day when something special is bringing in the crowds? At times you can walk onto a ride or into any show without a long wait, but at times the waits may be 45 minutes to an hour or longer. Finding a place to eat on busy days may make lunch take a couple hours rather than less than an hour etc.
With kids I would plan at least a couple hours for playing in the kids area. My sons loved what they had there when they were kids, still loved it on field trips through 6th or 7th grade, and would have thought what they have there now was one of the best play areas in the state.
Only you will know how much time you will want to spend in the shark encounter acquarium areas before you get to the tube, or down in the Wild Arctic area watching the animals. Sometimes in Wild Arctic we spend an hour or 2 if the bears are playing or swimming etc, if the walrus is coming up to the window and watching people, or if there is someone doing The Beluga adventure where they are in the water with the belugas. Sometimes we are in and out cause the crowds are big or the animals are not doing anything we want to keep watching. Sometimes we spend 5 minutes in underwater viewing areas and sometimes we spend hours. Depends on if the dolphin is making rings or they are playing with toys. Last time we were there (Christmas week) we ended up spending about an hour watching the sea lions. First time we ever saw one pick up a stone from the bottom and play catch with it. Then about 4 others started interracting with him and they sort of had a keep away game going. Fascinating . I would plan a couple days but be open to change plans if you think 1 day is all you really want to do after being there.