There are repeated parts in the assembly, such as the title.
This is not to represent each one ...
I want the same parts to be represented in one.
I just want to be able to check the quantity used for the count.
Is there any option in ST9 version?
You can right-click on the parts and pick 'Group' from the context menu.
Then rename the group to same as the parts.
Counting is not possible directly from the group though and you still have to use the Reports command on the Tools tab.
If there is only one list of parts, the length of the passfinder is shortened
It will be more convenient.
I guess there's only one way ...
No, it is not possible. Each occurrence of a part can have completely different occurrence properties, positions, relationships, etc. There is no way to maintain that uniqueness if you simply have a single entry in the Pathfinder that represents all occurrences of that part. If your goal is to reduce what you see in Pathfinder, Groups are probably your best option as Tushar suggested.
Would it be possible to pattern or use the "duplicate" command to pattern the parts in the assembly? If so, you would have on part in the tree.
If you want to check quantities in the assembly on the fly, you can pick on of the parts and then go up to the "select" pane and use the "select all identical parts" the count will show at the bottom of the screen.