I agree with Lou, I wouldn't worry about it untill the end of the season. For now just put some tape on to help keep the grease from flying out.
That said, though it's about a 2 hour job to remove the jet pump and drive shaft, replace that boot, and put it all about together. Possibly a bit longer if it's your first time. However while I was at it, I would change the pump oil which is easy, and probably check the engine alignment if you have an alignment tool. Obviously I would check the impeller and wear ring but not mess with it unless it shows wear.
Still if it's running good, you can post pone all the maintince untill the end of the season by just putting some tape around the gromet for now.
-TheChad