You could consider slightly altering your plans to sleep at the Portal the night before your hike (because it's right next to the trailhead) to spending the night before (or two would be even better) the hike at Horseshoe Meadows campgrounds at 10,000 feet which would help you acclimate so much more completely. It's a 50 minute drive down from there to the Whitney Portal (yes, I timed it) plus the sites are cheap $6 first come. If you stay two nights then you could do some light hiking in the area and take in the scenery and fresh air without exerting oneself too much. BTW, nothing I have read of or know from personal experience would indicate a hike to altitude a week before would have any effect or help with the acclimatization process whatsoever.
