I believe you can not use \today
or current date of the day or such commands
for adding the creation date for the todo comments. It is obvious by every
compile the date will change and we will lose the former creation time (or due time).
So maybe it is the best to write the time manually in your own defined template. I hope this helps:
\documentclass[a4paper]{article}
\usepackage[colorlinks]{hyperref}
\usepackage[colorinlistoftodos]{todonotes}
\newif\ifallowtodo
\begin{document}
\listoftodos
\allowtodotrue
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Nulla
\ifallowtodo \todo{Plain todonotes.\footnotesize{$\rightarrow$ \textit{Due Mar 22 '17}}} \else \fi
urna. Maecenas interdum nunc in augue. Mauris quis massa in ante
tincidunt mollis. Proin imperdiet. Donec porttitor pede id est. Sed
in ante. Integer id arcu. Nam lectus nisl, posuere sit amet,
imperdiet ut, tristique ac, lorem. In erat. In commodo enim.
\ifallowtodo \todo[color=blue!40]{Todonote with a different color. \footnotesize{$\rightarrow$ \textit{Due Sep 17 '16}}} \else \fi
Phasellus libero ipsum, tempor a, pharetra consequat, pellentesque
sit amet, sem. Praesent ut augue luctus elit adipiscing ultricies.
Vestibulum suscipit cursus leo. Nullam molestie justo.
\end{document}
\allowtodotrue
is just a flag for \ifallowtodo
to check whether we want
the todo mode or full pdf without todo. You can get rid of that if it is not
necessary.

\todo
's from different days? Wouldn't it be safer simply put date manually to each of them? – Przemysław Scherwentke Sep 12 '16 at 8:42