Robert, of the hundreds of people who visit Mt Whitney every week, only a few participate here. So finding someone to hike with here is unusual. However, once you are on the trail, you will find quite a few others heading up the same as you, so if you talk to people, you can probably find others who might hang together.
When you are camped at Trail Camp, you should take the time and talk to others there, and try to find others who want to leave about the same time in the morning. It is a big unknown, though, whether the others will hike at your same speed. You certainly won't be alone on the mountain, and so connecting with others should be pretty easy.