The short answer is it depends.
Insights you may gain at YC may help you either pivot or improve the current SaaS you have either from an offering or operational perspective.
Most importantly folow your gut feeling because that's what got you to $8.5k MRR. If there is even a 5% chance to improve your product or increase your revenue or both, you should take it. Define your success metric and proceed accordingly.
Hope this helps you :)