I see a few things in here that need to be clarified.
First and for most it doesn't matter how clean you make the sand by rinsing. Sand can and will get kicked up. The possibility is always there. Now there are a few things that you can do to avoid it such as turning the filter off(which you have to do anyway) when doing a water change.
However if you have any fish who play in the sand, that sand will get kicked up. Placing a sponge over may or may not be a good idea. The pros are that if it's big enough and it doesn't fill while you are away it prevents sand from getting in. It also throttles the current and can cause problems for cheaper units. That can be a con. If you don't catch it before the sponge clogs completely your filter will run dry and then run hot. You end up with a dead motor, and or possibly a fire hazard.
Now if you hike the intake you can help avoid some of the kicking up of sand getting into the motor. The side effect is your no longer have a proper current in some set ups. That in of itself can become it's own issue with still water or dead spots.
That's my input. If you go the sponge route don't get a dinky one. Or...get a different filtration system where it won't be an issue.