Dependents with only 4K and 3K in income

My 17-year-old was paid 4K as a 1099 employee.  
Can I put the whole thing in an IRA and not FILE taxes? Does it matter if I put it in a Roth or Regular IRA? 
Do we need to file?

He has filed before but never owed because he has never made more than 6K. 

 

Part 2- My 13- year old made 3K as a 1099 employee
What if I don't put it in an IRA, do we need to file his taxes?

He has never filed before.