The primary solution for adding a light and/or laser is using trigger guard-mounted accessories specifically designed for your firearm.
How to Install a Light and/or Light/Laser Combo
You cannot install a universal rail-mounted light/laser on your non-railed Ruger Max-9. Instead, you must purchase a product specifically made to clamp onto the trigger guard.
Purchase a compatible accessory: Look for products from manufacturers like *Crimson Trace* or *Viridian* that are explicitly advertised as fitting the non-railed Ruger Max-9. These are designed to wrap around the trigger guard and do not require a rail for mounting.
Follow the manufacturer's instructions: The installation process is straightforward, usually involving clamping the unit around the trigger guard and securing it with small screws. The product packaging or the manufacturer's website will have specific steps.

The lack of accessory rail pretty much limits you to trigger guard mounted systems. I do not know of and cannot find any light/laser combo unit meant for the Max-9. Usually something like a TLR-6 would be the answer here but they do not make one intended for the Max-9, have seen someone modify one meant for an M&P Shield with moderate success, but that would be at your own risk - model was 69273 just in case. For lasers only, there are models specifically for the Max-9 from Viridian, Crimson Trace, Lasermax, and possibly others.