I think that 9, 11 and 13 is quite young to be left alone for two evenings a week, particularly until after bedtime. I have a 9 yr old, and we leave her with adults only - - we don't consider young teens capable of truly adult supervision. Others will disagree, but when push comes to shove, it only matters if THESE kids are emotionally and developmentally ready to deal with your particular situation.
Your need for adult and 'off-duty' time is understandable. Their reluctance and difficulties are understandable as well - - many kids don't like being home alone. This is not an issue where I would be comfortable insisting on compliance; if a child says or indicates they aren't ready to be home alone or with near-age siblings, that would be that.
The benefits do not outweight the dangers, and it's common for kids to have trouble articulating their specific fears, insecurities or concerns. Sometimes kids are embarrassed to admit to 'silly' fears, or reluctant to rat out a sibling whose behavior is making them uncomfortable or afraid. We all like to think that OUR kids know they can tell us anything, but it's not always true.
One thing I would do is begin to slowly work towards more independence and quiet time on their part when you ARE home. This builds their own confidence and lessens your stress.
There are several things I'd address when it comes to leaving them alone for alone or couple time. I think that twice a week is a lot, so I'd probably dial that back to begin with. If you feel that it's needed, what others factors can be changed? I would consider:
*coming home before bedtime
*taking the phone calls in stride until they have more experience
*taking a few hours in the day on Saturday or Sunday - - dates don't have to be at night!
*hiring a sitter or having them go to a friend's house, rather than staying home alone
*having one of the times be date night, and the other time be alternating alone time for you and dh (with the other staying with the kids)
*asking the kids what would make it easier for them
I would also take a long hard look at outside activities. It sounds like a lot of time and energy goes into dealing with their sports teams, which perhaps aggravates the feeling of being over stretched and in need of a break. I would decide if the activity was important enough to consume that many family resources, and if the family as a whole can deal with the demands in good grace. If the answer to either question is no, curtailing or quitting some activities may be part of the answer.
Kids are not a grateful lot in general, ;), and their emotional needs are rarely 'reasonable.' It can indeed be frustrating when they seem unable to respond in a loving way to OUR needs and desires, but that immaturity is one of the reasons they are under our protection.