Squats

Without reference, it's hard to suggest anything, but if you're going ATG and still not activating glutes, is it possible you might be divebombing in the hole and relying on the rebound to bounce you out of the hole? If so, try slowing down the eccentric (tempo squats or pause squats) and once you hit depth, you can explode up to lock out each rep. Lock out by squeezing glutes before setting up for the next rep.

Alternatively, if you're a non-responder for whatever reason to squats, then supplement with glute bridges as an accessory movement to take legs out of the equation after squats, or if doing them on an alternate day.

its most likely a form issue.

That's pretty normal. Depending on your body shape, and a host of other factors you aren't necessarily going to feel squats a ton in your glutes, even if you are doing them "correctly". Add some more glute focused hinge pattern movements like deadlifts, hip thrusts and kettlebell swings.

I've always noticed more thigh soreness as well. I very rarely feel the pain in my glutes and wondered for a while if I was engaging them enough but progress pics have definitely shown a noticible difference!!! How long ago did you up your squat game? Have you worked with someone on your form? Progress pics really put things in perspective and over time you should be able to see some development P.s...Glute Bridges and Hip thrusts are amazing for the backside if you want some extra focus on the booty!

Could be form, could be that your glutes aren't as strong yet, could be lack of activation... Also squats are great but they are more quad focused. I feel them in my glutes quite a bit but only certain variations.. and it took time.

Also to build the booty, look into Strong Curves as bbell mentioned. However in order to gain size you will find the best results eating at maintenance or above.

It's hard to say without really seeing you squat. Assuming everything is fine, you can try going more low bar and you might notice a little more glute activation but probably not to the degree that you're interested in achieving. At the end of the day and regardless of bar position, your hips and knees flex and then you extend your knees and hips to get back up. The position of the bar changes the stimulus and movement a little. I think the MFP population puts too much emphasis on this aspect of squatting. Put the bar where it's comfortable and squat, it's not science.

To really put some emphasis on the glutes, you will probably want to do a couple other exercises to focus on them. Bret Contrares damn near has it down to a science, so his body of work is pretty solid and would be a good place to start.