Thank you for your email and my apologies for the later reply.
Specific to your question, NCAA Division I schools are allowed to send freshman 1 email or post mail a recruiting letter and/or recruiting questionnaire. Some schools will do that ASAP after receiving an outreach email, while others will wait a while because the recruit is just a freshman.
My inclination is that Ivy League schools may not be in a huge rush to respond to a freshman because they don't recruit super early, and also need to have more academic results to move forward in their recruiting efforts. If they come to an event, then that is just a bonus but again, I don't see the Ivy League making a determined effort to recruit freshman unless that freshman has stupid good physical skills.
As a freshman, the two best things you can do is keep developing your volleyball skill sets and keep attaining good grades. If you are reaching out to Ivy League schools, then academics are important to you and academics will play a huge role in your recruitment by Ivy League schools. The Ivy League has to recruit players who can academically be accepted into their school, no matter how physically talented they might be.
Being just a freshman, don't worry about the collegiate outreach right now - Focus on skills and grades. When you get into sophomore club, then start to reach out to college programs and make your reach out much broader than the Ivy League schools. The Ivy League is great, but there are so many other elite academic DI programs which should be under consideration.
Now, go practice and study!