1-you should be aware that AWR not exists in database 9i so you forced to use statepack, include to that steps to generate AWR much easier than STATPACK.
2-AWR hold all the information and statistics that exists in STATPACK, include to that AWR hold Additional Information.
3- in AWR you will find information called Active Session History ( ASH ) which is not exists in STATPACK.
4- To generate STATPACK you should Run Procedure to enable snapshot, you can use DBMS_JOB or schedule it using crontab.
5- AWR snapshots provide a persistent view of database statistics. A snapshot is a collection of performance statistics that are captured at a specific point in time,AWR snapshots are scheduled every 60 minutes by default.
6- Statspack snapshot purges must be scheduled manually otherwise AWR snapshots are purged automatically using MMON.