Jennifer,
The ladies have given you wonderful counsel. They have told you exactly what I would say.
When determining whether to return to workbooks, I would ask whether that will accomplish the goals you have for schooling your kiddo? Some parents honestly prefer workbooks because it is the simpler more straight-forward, get it done approach. When weighing the workbook option, it is also important to ponder whether workbooks really help you get to your child's heart? Meaning... do they inspire learning or thinking, after school is technically done for the day? Do they give you heart-changing moments where you share deeply? Workbooks used judiciously can be a great tool, but if your primary goal is to touch the heart of your kiddo and to help him interact with his material meaningfully (and with the Lord throughout his day), then another method is probably better.
My oldest is also very independent and really dislikes waiting for me, so I agree that teaching your oldest son to use the guide quite independently is a good option. But, I would make sure to do the portions that require discussion and interaction with him. If he would rather do his history readings and science readings on his own (at a different time than you have it scheduled with your other kiddos) I think thats o.k. too. Just make sure to do the oral questioning and discussion for history by either having him join you or by doing it separately at a different time with your son after he's read.
Keep the Bible study time together for Days 1 and 2 of each week and let him be independent on Days 3-4 (which are independent quiet time and copying the verse anyway). Let him do the Extension Pack reading on his own and the history project on his own too. Let him do the vocabulary, research, geography, and timeline mainly on his own too. But, check in with him daily and ask him the questions in the guide or check his product to make sure its done well.
Drawn into the Heart of Reading can be really independent at his age too, along with his math, and his science.
Try to schedule his times "with you" during a natural break in your schedule, so he isn't waiting on you. For example, you could meet with him right after lunch or right after a recess. Then, you won't be doing other things while he waits.
You could schedule a 20 min. or so "meeting time" in the morning (shortly after his history reading) and ask him any questions from the guide and briefly go over any independent work he's done that morning. Then, you could have a different 30 min. or so scheduled time during the afternoon to do dictation, do grammar, and briefly go over whatever he has done independently and turned in for the afternoon.
You could do poetry and storytime at lunch, so he'd already be there and participating with your other kiddos. Then, the only things he'd really join you for would be for some DITHR lessons and the first part of Bible each week.
Hope something in there gets you thinking of possibilities and helps!
If giving him more independence adds greatly to your schedule though, or if he doesn't do well working indpendently, then I'd just keep plugging along as is!
Blessings,
Carrie
. Now I don't want to hold him back, but I believe it's important that he learn to listen to the read alouds, narrate back, learn dictation skills, etc... 
I do encourage him to use the guide and check of the boxes as he completes them. It's tempting to give in to our oldest dc's independent nature because it is actually a wonderful quality most of the time, but I think if he did a workbook approach or if he blew through all of HOD on his own, he'd be missing some pretty important skills that are so important to learn - like even just working with other people to accomplish a task. Hope some of this helps!
. Everyday I see my little boy moving a little further from boyhood as he grows toward becoming a young man. 'Tis so bittersweet. I definitely want to reach is heart through our studies....as this is our main goal in our home schooling. 
