I use FormatDateTime function to display short dates. Here is what documentation says:
Display a date using the short date format specified in your computer's regional settings.
By default short date format on most computers is M/d/yyyy. Theoretically you can change regional settings to display date as MM/dd/yyyy however it won't affect how date is displayed on your remote Web server. If you need bulletproof solution you need to parse date values and display it manually.