While you may be allowed to bring a rollerboard now according to the rules, the odds of you being able to actually do so are pretty slim as the bins will likely be full by group 9.

ETA: Should also add, no the valet service is not going to be an option unless you're on a regional jet without normal sized bins (ie CRJ7, ER4) - so if they gate check it will be to bagage claim at your final.