The pain at the top of the boot is caused by your foot rolling inwards and the top of the boot pressing on the ankle. The quick fix for this is to heat up the top of the boot and roll this area outwards. Or pad the area with something like closed cell neoprene. However this doesn't fix the underlying issue of pronation. Heat molding does not fix pronation, you still pronate. All it does is help to straighten the ankle (as long as the boot fits well enough) but you are still pronating in the boot and over time, the constant pressure of the foot on the inside of the boot will eventually cause the boot to break down and open up. External shimming (between the boot and the holder, on the outside of the foot for pronation) isn't very well known in hockey circles yet is one of the first things you are evaluated for with any half decent figure coach and fitter. If you are struggling to find someone who can help you with shimming go ask someone in figure skating circles for a decent boot fitter.
Arch support (and orthotics) will also not fix your pronation, the arch support has nothing to lever against to provide the support for the foot. If you want it to help shape your foot then it will work but to help address pronation, no. Internal heel wedges (when used inside the boot they are placed on the inside of the heel for pronation) may help, it all depends on how much and how you pronate. Cheap to buy and you can experiment yourself, it's worth having a go. Shimming on the outside of the holder or moving the holder inwards or a mix of both are still the primary way to address pronation in skates.
There are a number of exercises to help pronation, they are all about strengthening the arch, ankle and calf. Here are 3:- One of them is to curl the toes inwards (imagine you are trying to touch the bottom of your heel with the bottom of your toes) as hard as you can and hold for 5 seconds then relax. Try to do 30 sets 3 times a day and as you get better, just keep doing as many as you can a day. Another is to find a ledge, put the inside of the foot on the ledge (first 2 toes and the ball of the foot, the outside of the foot hangs off the ledge) and then do calf raises whilst keeping the foot as level as you can. 30 sets 3 times a day. Another is to get a resistance band, sit on the floor and put it around a solid object and then around the top of your foot. Curl your foot towards you (without moving your leg, just your foot, imagine you want to try and get the top of your toes to touch your shin), hold for 5 seconds and then relax, repeat, 30 sets 3 times a day.
I can also give you a guaranteed fix for pronation in skates but it depends on how much you can skate / train and how dedicated you are to it. Start by dropping eyelets, say 2, then train until you get comfortable skating like this. Then drop another eyelet, repeat. You are aiming for 5 eyelets down, at this point you completely lose the support of the boot for the ankle. Now don't tie your laces at all. Learn to use your muscles to control your balance over the skate blade, stop relying on the boot to provide support. This will correct your pronation, guaranteed. Lace up for games, train unlaced. Ice or inline, it works for both.
If you don't have the time or inclination to do this and you don't want to shim (I personally do not like shimming) for whatever reason then buy the stiffest boots you can afford, tie them as tight as you can and go and skate. When the boots start to break down and open up then replace them. Depending on how hard you pronate and how often you skate will determine how long you get out of a pair of skates.