If I do not have dedicated ODC and Seat and working in Project do I need to stay 9 hrs or can do with 5 hrs.Manager not giving exceptions.

Be in the office for 9 hours and report to my base branch as required. If there's available space, I may work from the canteen or other free areas. If HR approaches me about not working in designated areas, I'll clarify the following points:
- My project doesn't have an ODC (Offsite Development Center) at this base branch.
- If HR suggests connecting with my project for seat allocation, I'll mention that I've already reached out and suggest that HR can contact the project team directly to resolve the issue.
- Given TCS's requirement for 9 hours of office work without a designated seat, I expect a reasonable workspace arrangement, rather than standing for the entire day."

I am taking WFH exception for the same reason

maintain wfo

Teams are getting consolidated at a few locations now.. if you or only a few people working for the project from a different location then sometimes the project may ask to relocate or else they release & backfill replacement. Some people may say if your skill is niche etc then you are okay but that only gives some additional time not permanent resolution.
On hours requirements talk to the manager to find an amicable solution for him and you both. Remember there is huge pressure on managers at this time and it's better to support each other than fall out.
Alternatively, i always say there are many great opportunities outside to keep hunting.
Only you can help yourself as you know your situation better than anyone else.
Hope this helps you! Best wishes!