It's assumed that you will be going through your run-up at the additional pavement adjacent to the hold-short area. This is why that area is there. If you taxi to the hold-short which includes a run-up area then you've obeyed the taxi clearance that was given to you. If you call up, "I'd like to spend a minute going through my pre-take-off checklist, the controller will simply scratch his head and think to himself, ok....what's your point? No ****! At least most would. Most GA traffic do their run-ups, most none-GA do not however and simply taxi directly to the hold-short and request clearance to take-off. If that's the case, let them pass, give it a second to let the turbulence pass and keep your distance but line up behind the ERJ, you can stay on ground till the your #1 for take-off or wait on tower, either way.
Once ERJ has taken off, call tower, ready for departure and it may be smart just to mention that you are taking a minute to wait for the wake turb to subside, just don't really need to wait too long but at least he's tracking why your ready but still sitting.
In the end, your the PIC, I've seen someone park behind an ERJ while driving a C172R because he was told to taxi to hold-short behind the ERJ, but instead of keeping his distance he was about the same distance he would normally be behind a GA. Once that ERJ ran his engine up, prior to crossing the hold-short that thrust blew the Cessna half a field away. Everyone was fine inside but the aircraft was totaled. So, if you want to sit in the run-up area just a little longer and wait for the ERJ to leave, it's your call and you don't gave to gain permission to do it.