[Liamwilko]

I may be wrong but for 9-10 months that's a massive weight. Mine is around 10 months and only around 175-200g (I've not weighed for about 3 weeks). Mine is a female but this still seems like a huge weight difference for the age.
They can go weeks without eating anything so a few days they aren't even sweating it. Have you tried chopping it really finely then putting mealworms underneath it so when he picks the worms up he takes the veg with it?

Try florets crispy salad mix, I have used it for years just pick the more stalky bits out, mine goes mad for the red leaves so I finely chop then she has to take mouthfuls of mixed leaves to get the red.

 

[Liamwilko]

I agree with Debbie I was about to say he looks like an adult and quite healthy. As suggested gut load your insects with the appropriate veggies and get them in him that way. I'd still continue to offer it then at least he has the choice to eat it or not.