Opening the score/notation view in PT9 is very very slow in large scoring templates. With over 100 tracks (or 200+), it may take 20-30 seconds to open the notation view for a single midi region. The key is the number of midi tracks. With scoring templates driving slave systems, VEPro, etc, that can run into the hundreds easily.
PT seems to have to scan and analyze every midi track anytime it goes to notation view.
This happens the first time any region is opened using "Open in Score Editor" (Alt-Win-=, or Opt-Cmd-=), and at first, PT displays every midi track in the score editor, which with 200 tracks, is a black mess of overlayed staves. Eventually it sorts things out after closing/reopening and you get the one track in the display. From there that track usually opens quickly.
When in the key editor, "Enable Notation Display" (button on upper left) also takes a long time, but it never speeds up - it's always slow, even when simply selecting/deselecting tracks in the track list with the key editor open. Usually 3-5 seconds to switch tracks within the KE, and 10 seconds at least to enable notation display after opening the KE (or to open the KE if notation display is already enabled from previous use).
This slowdown is irrespective of the number of midi regions - I could have one region in a new scoring project template, or hundreds of regions. All that matters is how many midi tracks are in the project.
With one or two midi tracks in the project, both open quickly enough.
But with 200-250, it's painfully slow. Takes a long time to transfer parts to Sibelius with this slowdown, though once the score editor is opened and you have the right view, transfer to Sibelius is as fast as opening Sibelius itself, and works well.