You could call the company that made the canopy for Vans Aircraft (Airplane Plastics) - in Tipp City, OH and get their advice:
Address: 9785 Julie Ct.
Tipp City, OH 45371
You will probably need to start with stop-drilling each end of the crack or cracks with a plexiglass drill bit. If done properly, and as long as the crack isn't a gaping crater, you should be able to fly it. I have two small cracks in my canopy on my RV4 that we're stop drilled by the previous owner 9 years ago and have held up fine. Yours, being on top of the canopy, you'll probably want to fill the crack to prevent rain water leakage while parked outside, and that's where Plane Plastics can help. You may even be able to fly it over to them (after its stop drilled), and have them seal it.
I have also called LP Aero Plastics in Pennsylvania for canopy installation advice when I was building my RV6. Even though it wasn't their product, they were very helpful with advice. They can answer your questions about products that are safe to use on sealing plexi:
RV6/2001 built/sold 2005
RV8 Fastback/2008 built/sold 2015
RV4/bought 2019 Flying
RV6/Used kit purchased 2021 building