You'd have to create a variable (datetime) with an operation that determines what your cut-off date is. So as an example, a check if date is older than 9 days:
[create variable (datetime)] » set variable to addDays( [%CurrentDateTime%] , -9) » $NineDaysAgo
[exculsive split] » compare $object/datetime <= $NineDaysAgo
Mendix has other pre-configured datetime variables such as BeginOfCurrentDay, week, month, year, as well as EndOfCurrentDay, week, etc.
You can just use the math functions for that. So >= is greater or equal. So you can use an exclusive split like this:
$dateToCheck >= $someOtherDate
You can also use tokens like [%CurrentDateTime%] in those expressions.