I don't fish but was a scout leader for years. Yes, season opens on April 8th. Best fishing is opening weekend and there will be people there at daybreak, but there should be good fishing throughout the spring. Stocked fish is safe but consider any native fish to be toxic. Groundwater in RI is bad. I believe you can get a fishing license at walmart or anywhere that sells gear. That used to be the case. If your kid catches their first fish, make sure you order the First Fish Award.

The RI DEM website has a lot of good advice for families.