After xray's told some osteopenia in both knees. Dr. Is referring me to an orthopaedic dr. For possible injections? Could physical therapy help?

Knee. Osteopenia is a reflection of a paucity of thickening of the cortices of the bone. It is sign that there may be some underlying osteoporosis. Injections such as hyaluronic acid (ha) in the knee are usually intended for osteoarthritis (oa) and not osteoporosis so I would be a little careful. You may want to gather further clarification from your doc especially if you do not have oa.
Osteopenia/arthritis. Osteopenia implies a decrease in typical bone density but is not severe as osteoporosis. It doesn't usually result in any pain. It is treated with calcium and vitamin d and weight bearing exercise like walking. Osteoarthritis is usually treated by orthopedic specialists with medications, injections, bracing and surgery for more severe cases. Physical therapy can indeed be beneficial for oa.
Yes...maybe. Depending on your symptoms, your orthopedic surgeon may recommend physical therapy as a first choice of treatment. Other options for treatment are injections and your md should discuss risks and benefits of the injections with you.