Sorry to hear about Axle's lameness and it is good that he is having x-rays as these will either rule in or out the various conditions that can cause lameness. It can be very worrying when a youngster pulls up lame and even more so in breeds or combination of these breeds (crossbreeds) that are prone to joint issues like Hip & Elbow Displaysia.
I also think you are doing the right thing by getting a second opinion, particularly if your boy is diagnosed with Hip Displaysia or an injury that may require surgery, like a ruptured/torn cruciate ligament.
A diagnosis of Hip Displaysia doesn't always mean worst case scenario and depending on the severity (Mild Displaysia, Moderate Displaysia or Severe Displaysia) it can be managed without medical or surgical intervention. The non medical management includes keeping the dog lean, putting them on chondrotin & glucosamine supplements (e.g. Jointguard or Glyde or human grade chrondrotin & glucosamine capsules/jointcare powder) and anti-inflammatory supplements like fish oil capsules. Also it is important that a displaystic dog gets regular exercise (walking and moderate running) to help build muscle around the joints to strengthem them. If the dog needed additional help to manage the displaysia with medical management, there are prescribed anti-inflammatories and Cartrophen Injections. I personally would never consider surgery for a dog diagnosed with mild displaysia and may be stretched to even consider it for moderate displaysia and I would be very wary of a vet or specialist (orthopaedic surgeon) that recommended surgery for a mild displastic dog.
Insofar as crating is concerned, keep an open mind, as depending on what your boy's diagnosis is, if any surgery is recommended and proceeded with, then you will really need to consider crating as an option to restrict your boy's movements for a specified period of time (surgery dependant) otherwise the surgery may be undone or complications caused by his unrestricted movement. Don't think of a crate in terms of a cage or how you would feel being caged, think of a crate as a tool to confine your dog to improve his chances of having a 100% uncomplicated recovery if he has to undergo surgery particularly. Anyway you will cross that bridge if you have to depending on what xrays reveal and vet/specialist recommendations.
Wishing you and Axle all the best and hope you receive some good news from the xrays. Keep positive and remember there are are many causes of lameness and some youngsters just injure themselves repeatedly without a worse case scenario diagnosis. You are both in my thoughts and I am sending lot of positive thoughts and healing vibes Axle's way.