Parking DC9s at the end of the summer is old news. They're currently reevaluating the fleet plan which could include parking more of them sooner. The current plan is to operate 68 of them. The ones they're parking are the oldest -30s which seat 100 seats. The ones they're keeping are the -40s and -50s at 110 and 125 seats respectively. The 900s and 175s were not acquired to be direct DC9 replacements. One could say the 900s were acquired to replace the Avros Mesaba flew. The bottom line is that 72, 76 seat jets are not going to replace a 100+ strong fleet of 100-125 seat a/c. NWA is currently evaluating a 100 seat replacement a/c, which is most likely the EMB195 or Cseries from BBd.
Having said all that... I wouldn't be surprised if NWA took options on the 175, 900 or both. However, the NWA current scope only allows for 90, 76 seaters to be operated meaning NWA could only bring on 18 more 76 seat a/c.
THe fleet plan for XJ is to operate 17 200s, 36 900s and 49 saabs. With that we'll need somewhere in the neighborhood of about 1100-1200 pilots. With our current seniority list about 1050 and classes filled through June, it's very likely hiring for the growth will end at the end of the summer. Hiring will however, likely continue to backfill for folks leaving for greener pastures, assuming that happens. If you got hired now, honestly, you'd be on the bottom of the list. Not a comfortable place to be when you enter a period of uncertainty. I wouldn't make a lateral move at this point. However, if you MUST get back to MSP, Mesaba is probably the best option.