I've assigned below macro.
%let date = 20090723(yymmddn8.)
but the question is the i want to change it in to Date ormat.
using this macro i need another variable "newdate" is in any type of Date format. like date9., mmddyy...........
Your final use of this data-string is unclear - so does the data need to be a SAS date variable with an internal representation (days since Jan 1, 1960) or are you expecting a formatted value (1/1/2009)?
Regardless, if you want to use SAS macro language only, you will need to look into using %SYSFUNC and at least the INPUT function to convert the character-representation to a SAS DATE value, and then if you also want to re-format the string to display a formatted DATE, you will again use %SYSFUNC and the PUTN function with the appropriate SAS format.
Suggest searching the SAS support http://support.sas.com/ website using keywords from the information provided in this post reply -- you will find both SAS-hosted documentation and also supplemental technical/conference papers on this topic.