@Mark_Bailey has shown the best solution. However, if you already have one or more data tables in JMP that have the incorrect values for the ID column, below is a very simple script that will convert the values
Names Default To Here( 1 );
dt = Current Data Table();
// Change the ID column to character
dt:ID << set data type( character );
// Loop through each row adding in the missing leading zeros
For Each Row(
:ID = Substr( "00000000", 1, 8 - Length( :ID ) ) || :ID;
);
Just swap out the reference to :ID to the actual name of your column
Jim