To add a space, use
[Parent Title] || ' ' || [Date Created]
http://www.kinook.com/UltraRecall/Ma...tem_titles.htm
Parent Title currently displays the template's parent title rather than the item's parent title. I don't think it was anticipated that it would be used in an item title expression.
It's not possible to include only a date and not the time for a date+time attribute.