No...he had to eat bugs and grubs when he lived with Timon and Pumbaa. Remember what Timon said "If you live with us, you have to eat like us" that was because they were not predators so they couldn't offer Simba a meal that a lion would prefer to eat. So when he returned to the Pride lands, he was surrounded by lions, predators, just like him so it was no use for eating grubs anymore, he must have passed to a carnivore diet. :)
No. Because female lions hunt 4 the pride. Why would you want a few little puny bugs to catch yourself when you can just sit around waiting for lionesses to bring back a nice meaty lunch.