Try to do what you can. Maybe you can get in 12-15 every other week or every third week. Maybe you just focus on long runs, LT and VO2 this time around and keep good records of your progression. Then maybe next time around you train for a fall marathon and with the longer days, you’re able to get in 12-15 instead of 8-9. Again, keep good records and compare the two.
Do the best you can, experiment, examine the results, make adjustments, repeat…